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MJHProject administrator Project developer Project scientist Send message
Joined: 12 Nov 07 Posts: 696 Credit: 27,266,655 RAC: 0 Level
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Hi everyone,
A couple of quick questions for those of you overclocking Geforce 680s
* What level of overclock have you observed being stable?
* Have any of you overclocked on a Linux system? If so, how did you do it?
Cheers!
Matt |
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On my GTX660Ti (same chip, almost same stock clock, same max voltage, probably slightly less) I'm running GPU-Grid and games at 1.175 V and 1.23 GHz. +15 MHz more occasionally failes a task, +30 MHz fails quickly. At POEM I can give it another 100 MHz.. but that's a very different (low) load.
MrS
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skgivenVolunteer moderator Volunteer tester
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Joined: 23 Apr 09 Posts: 3968 Credit: 1,995,359,260 RAC: 0 Level
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These GPU's auto-clock; they adjust their frequencies based on temperature and power. I noticed that after increasing the GPU fan speed, and adding a case fan, the GPU boost increased. I also changed the PSU (to a better one) and found that the GPU increased it's boost, slightly. It's now at 1200MHz and 1.175V. To go beyond that I would need to up the Voltage and manually force everything - something that is very much trial and error and GPU specific.
When running in Linux, I suggest you first worry about turning the fan control feature on, and if you work out how to overclocking, let the rest of us know.
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5potSend message
Joined: 8 Mar 12 Posts: 411 Credit: 2,083,882,218 RAC: 0 Level
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I have also observed around 1200 being a stable number.
I need to buy a new UPS before I can go for more. I think with my new system, I'm pretty much taking all it can handle.
I'm still not a big fan of the boost feature, but there's not much I can do about it. Dont want to actually mod my cards :(
Although, them running at 40C with liquid cooling is nice. |
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MJHProject administrator Project developer Project scientist Send message
Joined: 12 Nov 07 Posts: 696 Credit: 27,266,655 RAC: 0 Level
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Thanks for the replies all.
Skgiven- do you mean to say that the linux "coolbits" stuff still isn't working at all for the 680s?
Cheers,
MJH |
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skgivenVolunteer moderator Volunteer tester
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The last time I checked was with a GTX470 and the coolbits switch could only be used to set the fan speed, not the Voltage or Clocks. If this is still working for the GF600's it should still be useful though, as the fan rate controls temperature and because the GF600's clocks auto-adjust according to the temperature. The exact code might change from distro to distro.
In the distant past people have used tools to overclock GPU's by modifying the firmware while the card was in a Windows environment, hard-setting the clocks, and then installed the GPU into a Linux environment. Not something I would recommend trying on such an expensive card.
If I get the time I will have another poke at Linux.
- Although I was able to select prefer maximum performance in Ubuntu 12.10 with 310.x drivers I was not able to use coolbits to control the fan speed, never mind overclock the GPU. I also had to install Linux headers before installing the NVidia drivers, as the headers arn't in the iso, and following the guide I ended up with a 640x480 screen resolution which proved to difficult to work with. The reported speed of 705MHz must just be a reporting error as the run times were ~9% faster than on W7. This of course also proves that there is still a performance difference between W7/Vista and XP/Linux. I expect it's still >11%. The reason my runs were only ~9% faster could be that on W7 the turbo boost rises from the default of 1111MHz to ~1188MHz. I don't know what it really is on Linux, but it's certainly not 705MHz.
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