Database Users

Overclocking in Android - some questions and thoughts sharing

Hi all guys! I have a couple of questions and would like to hear some experiences and thoughts in general about overclocking in Android.
First a couple of more specific questions which I would like to have answered, if possible. If it's not possible, please give me your general thoughts anyway about overclock instead of moving to the next thread, please.
- Are there any kernels which allow overclocking beyond 1536 MHz?
- If so, did anybody try those frequencies? What was the result?
- Are there any people who for some reasons did NOT manage to have stable 1536 MHz?
- Are there any reliable reports of people frying their phones due to overclocking?
- Are there any easy ways to undervolt the CPU (at standard frequencies, not overclocked) in order to save some battery charge?
My very little OC experience is based on this: I have been running for some days a ROM based on a kernel which allowed OC up to 1536 MHz. I installed CPU Master Free, did some tests and found out, to my surprise, that the phone will run @1536 MHz without any noticeable issues. I never kept it at that frequency for more than 5 minutes I think, because I was afraid of excessive heat, but the phone never got really hot, just a bit warm. I ran some system benchmarks (Quadrant and another one which I can't recall right now) which stressed a bit the CPU and did not encounter any crashes. I also did this with performance governor which keeps the CPU constantly to the max frequency I think, and still no probs. Since everything works so fine and was that easy, I was wondering why don't everybody always run with the HD2 @1536 MHz. Is it only for battery issues? Please share your ideas about this and OC on the HD2 under Android in general.
Thanks.

The problem with overclocking isn't just overheating or too much power. With overclocking you are also increasing the say, amount of data being passed through the cpu. If the cpu's bus size isn't fast or big enough to handle it, it will ultimately slow down or malfunction.
So you should get the picture of overclocking now. Note however there are some safe speeds for overclocking.
Onto your next question as to why everyone doesn't overclock to the max speed. The reasons are: paranoia and safety of device
You have to know that not every chip is made exactly the same, they are modeled after the same design but are never made the same. So that mean whilst some people's phones may be able to handle extreme overclocking, like yours, others may not be able to, and malfunction/overheat. Malfunctioning like, cannot make phone calls, wifi/GPS doesn't work, etc.
So I hope this was informative.

Not everything you have said was new to me, but you were informative.
...although I would really be surprised to have issues with phone calls for instance caused by excessive overclocking...
Do you personally keep the HD2 overclocked?
Anybody else?

When I had my HD2, I rarely did so. Reason being is that I found no need to. The only times I did do so was to see if the phone actually was faster. In my results however I found no big difference so I didn't bother.

Well, the phone is indeed fast without OC, but you can feel the difference if you are performing some CPU intensive tasks. For example, unzipping a 200 MB ROM archive, or importing 1300 SMS from a backup. A temporary OC can save you maybe 1 minute or 30 secs, which aren't absolutely worth the time you spend learning to overclock the device, but never mind, even if you only saved 5 secs it's worth it for the satisfaction.

Ah I see your point. I was only looking in the perspective of simply tasks such as browsing internet/market, games, gallery.

Figure it this way. When you overclock a pc, (and if you're doing it safely/correctly) you have usually spent extra money on liquid cooling systems. Or at the very least, bigger fans, bigger heatsyncs, etc. Even with all that, you could very easily blow out a cpu or other component when you overclock.
Now, on a cell phone, you're running a MUCH higher risk. First off, there is NO extra cooling, and considering the size of our phones, and how thing they are, there's really no room for airflow. So while yes, it may work for you, in general I always say getting those couple extra frames per second out of your game are not worth the potential damage to the device.
Overclocking on actual computers has gotten much safer in the last few years, because the chip designers are putting more effort into keeping the chip cooler under load. Cell phones are not designed to overclock (even one as sweet as the hd2.)
Lastly, when overclocking a system (desktop), you usually change more than just the cpu clock speed. You'll usually have to adjust the voltage to compensate, and in some cases adjust memory timing as well as bus speed. None of this happens when you overclock on the hd2, all you do is change the clock speed.
It's not set in stone, but there's a very real possibility that you can do permanent damage to your device when overclocking. And, you may not notice the damage right away. Also keep in mind, these are mass produced cpu's, and there are slight variations in each chip. (Hence why some people can overclock higher and keep stability, while some phones with the same chip get picky if you even overclock 10mhz )
I've never seen the point in overclocking the hd2, you really don't get any real world speed out of it, it's a placebo at best. (And please don't start showing me or quoting benchmarks, they're useless, and extremely easy to make little changes in the roms to artificially boost benchmark scores.)
Edit: For more info, because I'm tired of typing, check these links:
http://en.wikipedia.org/wiki/Overclocking
http://www.webopedia.com/DidYouKnow/Computer_Science/2005/overclocking.asp

Great info mstrk242,
Thank you!

All benchmark info is skewed. Tried 1500mhz and the only app I noticed a difference on was gun bros. A new more efficient version of rom made it run fine at 998mhz. Not worth the extra wear and tear on your device. Simply changing things like your launcher can have larger effects.
Sent from my HyperDroid powered HD2!

Some vids I made featuring the DX...

Here are a few videos I made comparing the SPB Shell 3D launcher on my LG G2x to Go Launcher EX running on my Droid X. Enjoy...
http://www.youtube.com/watch?v=fxm-wwxQDSg
http://www.youtube.com/watch?v=AE8rGYwCxx4
http://www.youtube.com/watch?v=bKcUjPbepDE
http://www.youtube.com/watch?v=Ec0UWCoKzwo
http://www.youtube.com/watch?v=FTqF9fRXX1Q

Good job on the videos,
THANKS a lot for steering me clear of that $15 launcher, I totally agree that GO Launcher is better

GolfnWrx said:
Qualcomm has the fastest. If you compared the Droid X to a single 1GHz Snapdragon, you would also see that it is much smoother than the Droid X.
Click to expand...
Click to collapse
Incorrect...Have you ever used an HTC Incredible next to a Droid X? The Incredible (1GHz snapdragon) lags considerably with the same programs installed, even in similarly clean OS environment when compared to the DroidX.
Also, your next comment about how the DroidX is slower than old generation 600mhz processors is also totally false.

I'm sorry, don't mean to hijack your thread
Crobs,
No I haven't seen a stock Incredible, what I have seen is an Incredible S, it runs over 30 MFLOPS and I think it's totally stock (may have custom ROM, it belongs to a guy at work). I also don't know what the difference is between an Incredible and an "S".
My son's Optimus running Cyogen 7 runs a Linpack score of 36 MFLOPS. NOTE: The old V6 CPU is actually an 800 MHz CPU that is clocked at 600 MHz, it is slowed down to conserve battery, I know my son is running at 800 MHz, so his battery is life is shortened.
The best I have run (I've tried several different ROMs) is 16...not even 1/2 of what either of them is scoring...right now I'm back to stock running 12 MFLOPS.
Also all of the ROM's I've tried have had issues, reboots, shutdowns, won't turn off, market doesn't work, WIFI, won't push email, etc....just random stuff, I need my phone to work, my son's phone works perfectly and is much faster than mine.
I will accept that you say the Droid-X can run with the Snapdragon, can you tell me which ROM is stable and will run 30+ MFLOPS? Because so far I haven't seen it, and I want to.
Thanks.

GolfnWrx said:
Crobs,
No I haven't seen a stock Incredible, what I have seen is an Incredible S, it runs over 30 MFLOPS and I think it's totally stock (may have custom ROM, it belongs to a guy at work). I also don't know what the difference is between an Incredible and an "S".
My son's Optimus running Cyogen 7 runs a Linpack score of 36 MFLOPS. NOTE: The old V6 CPU is actually an 800 MHz CPU that is clocked at 600 MHz, it is slowed down to conserve battery, I know my son is running at 800 MHz, so his battery is life is shortened.
The best I have run (I've tried several different ROMs) is 16...not even 1/2 of what either of them is scoring...right now I'm back to stock running 12 MFLOPS.
Also all of the ROM's I've tried have had issues, reboots, shutdowns, won't turn off, market doesn't work, WIFI, won't push email, etc....just random stuff, I need my phone to work, my son's phone works perfectly and is much faster than mine.
I will accept that you say the Droid-X can run with the Snapdragon, can you tell me which ROM is stable and will run 30+ MFLOPS? Because so far I haven't seen it, and I want to.
Thanks.
Click to expand...
Click to collapse
You're right, I really wish I had 30+ MFLOPS so I could send texts, emails and browse the internet. Oh wait, any phone can already do that.

crobs808 said:
You're right, I really wish I had 30+ MFLOPS so I could send texts, emails and browse the internet. Oh wait, any phone can already do that.
Click to expand...
Click to collapse
I have some code written to upload a program for ladder logic in our automated warehouse (ladder logic is what mechanical engineers think programming is).
On my G1 it took about 40 minutes to run. On my droid-x it runs a under 15 mins. If I use a laptop I can run it in about 5 mins, but that means I have to haul a laptop on a 60 foot climb to the top of the scafolding to the controller, it's not so easy, so if I can get it to run from a Linux phone it's easier, in fact I used to use my 40 minute G1 to do it instead of hauling a laptop up there.

I am very familiar with ladder logic. I am a QA Engineer for security software and one of the panels we integrate to uses ladder logic behind the scenes for configuration of access to doors and readers.
At any rate - it seems like you should be taking a Netbook up there with you, or a tablet.
My original point stands - you are trying to us a phone to do what a computer or tablet should be doing. I hear complaints on these forums all the time where people buy a phone then they are dissapointed that it cannot remote start their car....um, like come on you bought a PHONE! what did you expect.
Also, you need to stop going around to all the new posts and posting that Qualcomm is better than DroidX. If you don't like it just keep it to yourself - your comments aren't helping anyone.

1.3/1.4GHz+

I keep hearing about people running their nooks at 1.3 or 1.4 but I can't find a kernel. Any help here?

I've been a member a long time and I know that bumping your own thread is not generally accepted, however, I have reason to believe that this device can bump WAY past the current speeds. For one, I have read articles claiming 2800 on Quad at 1.3 and that 1.4 kernels were being worked on and two - even under the HEAVIEST load, while charging no less, my phone hits 38C on the battery. My brand spanking new Sensation hits 47C when its charging and being used!

While it IS possable to overclock to 1.3+ ghz, it is not usually advised. I run CM7 7.1 rc1 and have dalengrins overclock rom dated 06/18 it has been my experience that speeds over 1.2 ghz reduce the stability of the nook and can cause strange behaviour. My quadrant scores at the above mentioned 1.2 average between 2550 and 2875. Considering these scores are almost 3 times the score of a stock rooted nook, I have no problem with the speed. The only time my nook reaches those speeds is when I am playing games from the tegrazone areas. Currently, I have 3 "tegra only" games running quite well. For a 7 inch e-reader, I believe that is acceptable.
Sent from my NookColor using Tapatalk

Moshe5368 said:
While it IS possable to overclock to 1.3+ ghz, it is not usually advised. I run CM7 7.1 rc1 and have dalengrins overclock rom dated 06/18 it has been my experience that speeds over 1.2 ghz reduce the stability of the nook and can cause strange behaviour. My quadrant scores at the above mentioned 1.2 average between 2550 and 2875. Considering these scores are almost 3 times the score of a stock rooted nook, I have no problem with the speed. The only time my nook reaches those speeds is when I am playing games from the tegrazone areas. Currently, I have 3 "tegra only" games running quite well. For a 7 inch e-reader, I believe that is acceptable.
Sent from my NookColor using Tapatalk
Click to expand...
Click to collapse
I thank you for the response and I understand your concern, however, I have been able to undervolt an extra 100mV off of the voltage at 1200MHz with 15 runs of Quadrant and no freezing and would like to use the wiggle room that I have. I undervolted by 200mV and ended up running 6 before it froze so obviously this is one of the better chips as far as overclocking.
That said, it beats my Sensation's 1.2GHz out of the box which says a lot. My Sensation at 1.2GHz is about 1900 and I feel this processor can go farther.
We also need new drivers for the SGX530. There is NO reason why it should be running 9 FPS average at stock AND overclocked on the simplest bench on Quad (the planet and moon test which fragments and everything).
I'm about to pay for Chainfire's app so that I can see if Pinball 3D will run on here... if it does and its smoother than on my G2x which HAS a Tegra and misses my input a LOT then I will be more than happy.
Its really more for bragging rights than anything to have this thing clocked clock-for-clock with the new gen "dualcores" and have it whip their asses honestly LOL

I think my Note is underutilize.

I was curious about how application utilize my Note capability, so I install CPU spy and reset timer. After that I played Mass Effect Infiltrator and Anomaly for 30 minutes. What make me very surprise is most of the time (almost 50%) Android is running on 500 Mhz. Only 20% of the time running on 800 Mhz and 30% running on 200 Mhz. My whole life is a lie ! Let alone GPU which I underclock to 200 Mhz, Why Samsung bother market dual-core 1,2 Ghz or even Quad-core 1,4 Ghz while HD 2012 Games only need dual-core 500 Mhz to run It smoothly. Is there any apps (beside benchmark) that fully utilize my Note ? Thank you.

Lol you should thank the developers of that game that they optimized code to run at 500mhz. If they made it use more your battery would drain more.
Youre thinking is different, its the game, not the phone that underutilizes lmao
Sent from my GT-N7000 using Tapatalk 2

I almost fell off my chair when i read the OP..
developers are trying their best to develop games, apps that are beneficial to users like us..
Now u are complaining that game run on less memory n RAM..
on the other hand if the game would to ultilise high RAM, high batt comsumption or high memory usage,wat will b ur stand?
If u reali think u had under ultilisrd ur Note, mayb u should sit down and think whether to sell it n get a phone that u can "fully ultilise" it

There Are Multiple Possinilities Actually
ramabg said:
I was curious about how application utilize my Note capability, so I install CPU spy and reset timer. After that I played Mass Effect Infiltrator and Anomaly for 30 minutes. What make me very surprise is most of the time (almost 50%) Android is running on 500 Mhz. Only 20% of the time running on 800 Mhz and 30% running on 200 Mhz. My whole life is a lie ! Let alone GPU which I underclock to 200 Mhz, Why Samsung bother market dual-core 1,2 Ghz or even Quad-core 1,4 Ghz while HD 2012 Games only need dual-core 500 Mhz to run It smoothly. Is there any apps (beside benchmark) that fully utilize my Note ? Thank you.
Click to expand...
Click to collapse
If you are not aware, off the apps portion, there are apps from market that transform your phone into:
1. Vibrator - https://play.google.com/store/apps/details?id=cenix.android.vbr&feature=search_result
2. Security Alarm - https://play.google.com/store/apps/...honeSecurityAlarmSystem&feature=search_result
3. Police Siren - https://play.google.com/store/search?q=security+Alarm&c=apps
I mean just to name a few, instead of benchmarking your phone, maybe it can be made for good cause when it is not performing telepony duty

[email protected] for android

I think its a good, I've underclocked my note to 1000 MHz and haven't notcied any difference in performance at all even during gameplay, saves loads of battery aswell. Might even drop it too 800 mhz to see if I can get away with that.

lewisteo said:
If you are not aware, off the apps portion, there are apps from market that transform your phone into:
1. Vibrator - https://play.google.com/store/apps/details?id=cenix.android.vbr&feature=search_result
2. Security Alarm - https://play.google.com/store/apps/...honeSecurityAlarmSystem&feature=search_result
3. Police Siren - https://play.google.com/store/search?q=security+Alarm&c=apps
I mean just to name a few, instead of benchmarking your phone, maybe it can be made for good cause when it is not performing telepony duty
Click to expand...
Click to collapse
Lol vibrator @1400hz lmao, imagine that :what::beer::thumbup:
Sent from my GT-N7000 using Tapatalk 2

Do you overclock your N7?

Do you?
Do you keep it overckocked for a longer period, permanently, or just when/while you need it? How much (exact frequencies would be cool) I'm thinking of OCing mine (both CPU and GPU) since some games like NOVA 3 lag on occasions but not sure how safe/advisable it is.
Sent from my Nexus 7 using Tapatalk HD

I don't think it's needed. I've heard that OC won't help much with gaming, but you can definitely try

I don't yet - I might later. My N7 is still less than a month old.
The device manufacturers (e.g. Asus in this case) have motivations to "not leave anything on the table" when it comes to performance. So, you have to ask yourself - why would they purposely configure things to go slowly?
After all, they need to compete with other handset/tablet manufacturers, who are each in turn free to go out and buy the exact same Tegra SoC (processor) from Nvidia.
At the same time, they know that they will manufacture millions of units, and they want to hold down their product outgoing defect levels and in-the-field product reliability problems to an acceptable level. If they don't keep malfunctions and product infant mortality down to a fraction of a percent, they will suffer huge brand name erosion problems. And that will affect not only sales of the current product, but future products too.
That means that they have to choose a conservative set of operating points which will work for 99+ % of all customer units manufactured across all temperature, voltage, and clock speed ranges. (BTW, Note that Asus didn't write the kernel EDP & thermal protection code - Nvidia did; that suggests that all the device manufacturers take their operating envelope from Nvidia; they really don't even want to know where Nvidia got their numbers)
Some folks take this to mean that the vast majority of units sold can operate safely at higher speeds, higher temperatures, or lower voltages, given that the "as shipped" configuration will allow "weak" or "slow" units to operate correctly.
But look, it's not as if amateurs - hacking kernels in their spare time - have better informed opinions or data about what will work or won't work well across all units. Simply put, they don't know what the statistical test properties of processors coming from the foundry are - and certainly can't tell you what the results will be for an individual unit. They are usually smart folks - but operating completely in the dark in regards to those matters.
About the only thing which can be said in a general way is that as you progressively increase the clock speed, or progressively weaken the thermal regulation, or progressively decrease the cpu core voltage stepping, your chances of having a problem with any given unit (yours) increase. A "problem" might be (1) logic errors which lead to immediate system crashes or hangs, (2) logic errors (in data paths) that lead to data corruption without a crash or (3) permanent hardware failure (usually because of thermal excursions).
Is that "safe"?
Depends on your definition of "safe". If you only use the device for entertainment purposes, "safe" might mean "the hardware won't burn up in the next 2-3 years". Look over in any of the kernel threads - you'll see folks who are not too alarmed about their device freezing or spontaneously rebooting. (They don't like it, but it doesn't stop them from flashing dev kernels).
If you are using the device for work or professional purposes - for instance generating or editing work product - then "safe" might mean "my files on the device or files transiting to and from the cloud won't get corrupted", or "I don't want a spontaneous kernel crash of the device to cascade into a bricked device and unrecoverable files". For this person, the risks are quite a bit higher.
No doubt some tool will come in here and say "I've been overclocking to X Ghz for months now without a problem!" - as if that were somehow a proof of how somebody else's device will behave. It may well be completely true - but a demonstration on a single device says absolutely nothing about how someone else's device will behave. Even Nvidia can't do that.
There's a lot of pretty wild stuff going on in some of the dev kernels. The data that exists as a form of positive validation for these kernels is a handful of people saying "my device didn't crash". That's pretty far removed from the rigorous testing performed by Nvidia (98+% fault path coverage on statistically significant samples of devices over temperature, voltage, and frequency on multi-million dollar test equipment.)
good luck!
PS My phone has it's Fmax OC'ed by 40% from the factory value for more than 2 years. That's not a proof of anything really - just to point out that I'm not anti-OC'ing. Just trying to say - nobody can provide you any assurances that things will go swimmingly on your device at a given operating point. It's up to you to decide whether you should regard it as "risky".

Wow thanks for your educational response, I learned something. Great post! I will see if I will over clock it or not since I can play with no problems at all, it is just that it hics up when there is too much stuff around. Thanks again!
Sent from my Nexus 7 using Tapatalk HD

With the proper kernel its really not needed. Havent really seen any difference,aside from benchmark scores(which can be achieved without oc'ing)
Sent from my Nexus 7 using XDA Premium HD app

Yes, I run mine at 1.6 peak.
I've come to the Android world from the iOS world - the world of the iPhone, the iPad, etc.
One thing they're all brilliant at is responsive UI. The UI, when you tap it, responds. Android, prior to 4.1, didn't.
Android, with 4.1 and 4.2, does. Mostly.
You can still do better. I'm running an undervolted, overclocked M-Kernel, with TouchDemand governor, pushing to 2 G-cores on touch events.
It's nice and buttery, and renders complex PDF files far faster than stock when the cores peak at 1.6.
I can't run sustained at 1.6 under full load - it thermal throttles with 4 cores at 100% load. But I can get the peak performance for burst demands like page rendering, and I'm still quite efficient on battery.
There's no downside to running at higher frequencies as long as you're below stock voltages. Less heat, more performance.
If you start pushing the voltages past spec, yeah, you're likely into "shortening the lifespan." But if you can clock it up, and keep the voltages less than the stock kernel, there's really not much downside. And the upside is improved page rendering, improved PDF rendering, etc.
Gaming performance isn't boosted that much as most games aren't CPU bound. That said, I don't game. So... *shrug*.

Bitweasil said:
I can't run sustained at 1.6 under full load - it thermal throttles with 4 cores at 100% load.
Click to expand...
Click to collapse
@Bitweasil
Kinda curious about something (OP, allow me a slight thread-jack!).
in an adb shell, run this loop:
# cd /sys/kernel/debug/tegra_thermal
# while [ 1 ] ; do
> sleep 1
> cat temp_tj
> done
and then run your "full load".
What temperature rise and peak temperature do you see? Are you really hitting the 95C throttle, or are you using a kernel where that is altered?
I can generate (w/ a mutli-threaded native proggy, 6 threads running tight integer loops) only about a 25C rise, and since the "TJ" in mine idles around 40C, I get nowhere near the default throttle temp. But I am using a stock kernel, so it immediately backs off to 1.2 Ghz when multicore comes on line.
Same sort of thing with Antutu or OpenGL benchmark suites (the latter of which runs for 12 minutes) - I barely crack 60C with the stock kernel.
?
bftb0

The kernel I'm using throttles around 70C.
I can't hit that at 1200 or 1300 - just above that I can exceed the temps.
I certainly haven't seen 95C.
M-Kernel throttles down to 1400 above 70C, which will occasionally get above 70C at 1400, but not by much.

Bitweasil said:
The kernel I'm using throttles around 70C.
I can't hit that at 1200 or 1300 - just above that I can exceed the temps.
I certainly haven't seen 95C.
M-Kernel throttles down to 1400 above 70C, which will occasionally get above 70C at 1400, but not by much.
Click to expand...
Click to collapse
Thanks. Any particular workload that does this, or is the throttle pretty easy to hit with arbitrary long-running loads?

Odp: Do you overclock your N7?
I'll never OC a quadcore phone/tablet, I'm not stupid. This is enough for me.
Sent from my BMW E32 using XDA App

I've over clocked my phone, but not my N7. I've got a Galaxy Ace with a single core 800MHz processor OC'd to 900+. The N7 with its quad core 1.3GHz is more than enough for doing what I need it to do. Using franco.Kernel and everything is smooth and lag-free. No need for me to overclock
Sent From My Awesome AOSPA3.+/franco.Kernel Powered Nexus 7 With XDA Premium

Impossible to do so can't even get root but did manage to unlock the bootloader
Sent from my Nexus 7 using xda app-developers app

CuttyCZ said:
I don't think it's needed. I've heard that OC won't help much with gaming, but you can definitely try
Click to expand...
Click to collapse
I'm not a big OC'er, but I do see a difference in some games when I OC the GPU. It really depends on the game and what is the performance bottleneck. If the app is not Kernel bound than an OC won't make much difference. Must games are I/O and GPU bound.
Sent from my N7 using XDA Premium
Dirty AOKP 3.5 <&> m-kernel+ a34(t.10)

I've overclocked all of my devices since my first HTC hero. I really don't see a big deal with hardware life.
I know that this n7 runs games better at 1.6ghz than at 1.3ghz.
First thing I do when I get a new device is swap recovery and install aokp with the latest and greatest development kernel. Isn't that why all this great development exists? For us to make our devices better and faster? I think so. I'd recommend aokp and m-kernel to every nexus 7 owner. I wish more people would try non-stock.

scottx . said:
I've overclocked all of my devices since my first HTC hero. I really don't see a big deal with hardware life.
I know that this n7 runs games better at 1.6ghz than at 1.3ghz.
First thing I do when I get a new device is swap recovery and install aokp with the latest and greatest development kernel. Isn't that why all this great development exists? For us to make our devices better and faster? I think so. I'd recommend aokp and m-kernel to every nexus 7 owner. I wish more people would try non-stock.
Click to expand...
Click to collapse
Do you mean the pub builds of AOKP? Or Dirty AOKP
Ty

bftb0 said:
Thanks. Any particular workload that does this, or is the throttle pretty easy to hit with arbitrary long-running loads?
Click to expand...
Click to collapse
Stability Test will do it reliably. Other workloads don't tend to run long enough to trigger it that I've seen.
And why is a quadcore magically "not to be overclocked"? Single threaded performance is still a major bottleneck.

Bitweasil said:
Stability Test will do it reliably. Other workloads don't tend to run long enough to trigger it that I've seen.
And why is a quadcore magically "not to be overclocked"? Single threaded performance is still a major bottleneck.
Click to expand...
Click to collapse
Hi Bitweasil,
I fooled around a little more with my horrid little threaded cpu-blaster code. Combined simultaneously with something gpu-intensive such as the OpenGL ES benchmark (which runs for 10-12 minutes), I observed peak temps (Tj) of about 83C with the stock kernel. That's a ridiculous load, though. I can go back and repeat the test, but from 40C it probably takes several minutes to get there. No complaints about anything in the kernel logs other than the EDP down-clocking, but that happens just as soon as the second cpu comes on line, irrespective of temperature. With either of the CPU-only or GPU-only stressors, the highest I saw was a little over 70C. (But, I don't live in the tropics!)
To your question - I don't think there is much risk of immediate hardware damage, so long as bugs don't creep into throttling code, or kernel bugs don't cause a flaw that prevents the throttling or down-clocking code from being serviced while the device is running in a "performance" condition. And long-term reliability problems will be no worse if the cumulative temperature excursions of the device are not higher than what than what they would be using stock configurations.
The reason that core voltages are stepped up at higher clock rates (& more cores online) is to preserve both logic and timing closure margins across *all possible paths* in the processor. More cores running means that the power rails inside the SoC package are noisier - so logic levels are a bit more uncertain, and faster clocking means there is less time available per clock for logic levels to stabilize before data gets latched.
Well, Nvidia has reasons for setting their envelope the way they do - not because of device damage considerations, but because they expect to have a pretty small fraction of devices that will experience timing faults *anywhere along millions of logic paths* under all reasonable operating conditions. Reducing the margin, whether by undervolting at high frequencies, or increasing max frequencies, or allowing more cores to run at peak frequencies will certainly increase the fraction of devices that experience logic failures along at least one path (out of millions!). Whether or not OC'ing will work correctly on an individual device can not be predicted in advance; the only thing that Nvidia can estimate is a statistical quantity - about what percent of devices will experience logic faults under a given operating conditon.
Different users will have different tolerance for faults. A gamer might have very high tolerance for random reboots, lockups, file system corruption, et cetera. Different story if you are composing a long email to your boss under deadline and your unit suddenly turns upside down.
No doubt there (theoretically) exists an overclocking implementation where 50% of all devices would have a logic failure within (say) 1 day of operation. That kind of situation would be readily detected in a small number of forum reports. But what about if it were a 95%/5% situation? One out of twenty dudes report a problem, and it is dismissed with some crazy recommendation such as "have you tried re-flashing your ROM?". And fault probability accumulates with time, especially when the testing loads have very poor path coverage. 5% failure over one day will be higher over a 30 day period - potentially much higher.
That's the crux of the matter. Processor companies spend as much as 50% of their per-device engineering budgets on test development. In some cases they actually design & build a second companion processor (that rivals the complexity of the first!) whose only function is to act as a test engine for the processor that will be shipped. Achieving decent test coverage is a non-trivial problem, and it is generally attacked with extremely disciplined testing over temperature/voltage/frequency with statistically significant numbers of devices - using test-vector sets (& internal test generators) that are known to provide a high level of path coverage. The data that comes from random ad-hoc reports on forums from dudes running random applications in an undisciplined way on their OC'ed units is simply not comparable. (Even "stressor" apps have very poor path coverage).
But, as I said, different folks have different tolerance for risk. Random data corruption is acceptable if the unit in question has nothing on it of value.
I poked my head in the M-kernel thread the other day; I thought I saw a reference to "two units fried" (possibly even one belonging to the dev?). I assume you are following that thread ... did I misinterpret that?
cheers

I don't disagree.
But, I'd argue that the stock speeds/voltages/etc are designed for the 120% case - they're supposed to work for about 120% of shipped chips. In other words, regardless of conditions, the stock clocks/voltages need to be reliable, with a nice margin on top.
Statistically, most of the chips will be much better than this, and that's the headroom overclocking plays in.
I totally agree that you eventually will get some logic errors, somewhere, at some point. But there's a lot of headroom in most devices/chips before you get to that point.
My use cases are heavily bursty. I'll do complex PDF rendering on the CPU for a second or two, then it goes back to sleep while I read the page. For this type of use, I'm quite comfortable with having pushed clocks hard. For sustained gaming, I'd run it lower, though I don't really game.