SAPPHIRE HD 7950 3GB GDDR5 (11196-01) Undervolting in linux

minefish

newbie

Activity: 50

Merit: 0

If I remember correctly I saved about 150 Watts Total going from 3*7950 @ 1.250v to 3*7950 @ 1.087v

Undervolting does not affect you're hashing speed directly.

Though with a lower core voltage you will not be able to clock you're GPU clock as high as with a higher core voltage.

In my case it did not affect my hashing speed at all.

First I found my highest Memory Clock speed and its correlating GPU clock.

Only then as a final step I lowered the voltage.

I wrote a guide on how to overclock/undervolt you're 7950 and 7850 in Windows 7/8.

https://bitcointalksearch.org/topic/how-to-ltc-mining-overclocking-guide-79507850-175646

melmo

full member

Activity: 213

Merit: 100

Any idea how much power you saved by undervolting? And how big a hit to the mhash was it?

Quote from: minefish on April 26, 2013, 04:07:05 PM

Hi Jason,

I read somewhere that you can't undervolt radeon 7xxx cards in linux.

(you should verify though)

I personally had the same issue in ubuntu with a 3x7950 (SAPPHIRE 7950 HD 3L) therefore I switched to windows 7
so I could easily undervolt them with Sapphire Trixx.

minefish

newbie

Activity: 50

Merit: 0

Hi Jason,

I read somewhere that you can't undervolt radeon 7xxx cards in linux.

(you should verify though)

I personally had the same issue in ubuntu with a 3x7950 (SAPPHIRE 7950 HD 3L) therefore I switched to windows 7
so I could easily undervolt them with Sapphire Trixx.

jasonpitts

newbie

Activity: 23

Merit: 0

Hi,

I have 3 of these cards and from everything I have read they are voltage unlocked, but I cannot get it to budge from 1.25VDC. The only tool that I know about to do it is atitweak,

https://bitcointalksearch.org/topic/new-command-line-tool-for-overclocking-ati-cards-linux-25750

but I have no luck at all.

Does anyone have any experience or suggestions?

Thanks,
-Jason

Topic: SAPPHIRE HD 7950 3GB GDDR5 (11196-01) Undervolting in linux (Read 6100 times)