Downclocking a 780 Ti

[Nicolas_orleans]

Linux driver 337.12 beta has support for over/down clocking, and starting with the 337 release, next releases will also have this support.
I did not yet install ubuntu 14.04 lts, so I don't know if the 337 release is proposed in the system settings / software and updates / additionnal drivers
Also I did not check xorg edgers ppa for this release

What you could do, assuming your OS is Ubuntu, is
1/download 337.12 from nvidia website
2/press Ctrl+Alt+F1 to close GUI and open command line interface
3/shutdown the graphics environment by typing

Code: Select all

sudo service lightdm stop

4/locate the directory where you saved the file and name of the file (assuming NVIDIA-Linux-x86_64-337.12-pkg1 for below command)
5/execute file

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sudo sh ./NVIDIA-Linux-x86_64-337.12-pkg1.run

6/start the graphics environment again

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sudo service lightdm start

7 go back to GUI by pressing Ctrl+Alt+F7


If not Ubuntu, you will need to edit step 3/ with whatever your distro is using to provide equivalent of lightdm service under ubuntu

I would recommend to read http://www.phoronix.com/scan.php?page=n ... px=MTY1OTM on how to use the driver for offsetting the clock speed (over/down clocking)

[billford]

Thanks for that.

I'm normally a bit wary of beta drivers but I'd prefer to stick with Linux so it's definitely worth a try.

[billford]

After about 5 unsuccessful attempts I decided that Mint doesn't like manual installation of device drivers… so I installed Ubuntu instead and it went like clockwork

I can confirm that with the 780 Ti, version 337.12 supports tweaking of both the graphics and memory clocks, also fan speed control (coolbits set to 12).

But I noticed something odd, which I'd like some advice about. According to the Gigabyte website, my card has a base clock of 1020MHz with a boost to 1085MHz. According to the PowerMizer it normally runs at 1163MHz and I've never seen it below 1150MHz.

If that's to be believed, my already factory overclocked card is running with a further overclock of nearly 80MHz which, if true, might explain quite a bit!

I've put in an offset of -78MHz and it says it's now running at 1085MHz, (memory still at 7000MHz) but it's not running any cooler (though the TPF has increased by about the right amount)… I can't understand what's going on?

edit- And I can't affect the memory at all, it stays at 7000 whatever I enter.

[Nicolas_orleans]

Glad this worked for you billford !

In my own experience, what is advertised by manufacturers is the MINIMUM overclock of the chips they put in their graphic cards.

My GTX 770s were sold as "stock chips" (no price premium for advertised factory OC) but run at 1137 MHz and 1150 MHz (better than some "OCed" cards sold at higher price). There used to be reports of inaccurate speeds in Power Mizer but they were fixed around 319.xx

Did you see a TPF increase when downclocking to 1085 MHz ?

[bruce]

@billford:

You probably already know this, but increasing VRAM speed produces a very small improvement in FAH's speed concurrent with a measurable increase in heat (and Watts). Processor speed is what's important.

[billford]

@Nicolas_orleans:

Yes, it's behaving (performance-wise) as expected, just not any cooler!

@bruce:

Yes, but I'm trying to decrease the VRAM speed and it won't let me

It's probably deliberate- for the indicated performance level (3) the max and min speeds are the same at 7000MHz, and there's no obvious way to change either the range or the performance level.

[bruce]

The feature to underclock RAM will be incorporated into Version N+1.

[billford]

Is that due Real Soon Now?