7950 MSI TwinFrozr : Undervolt and Overclock

[icebear888]

Hi all

I have 2 of these cards in my rig. Im trying to manage the power consumption as best I can.
Someone said that I can undervolt and still overclock these cards.

How much do I undervolt it?
And how much do I overclock it?

Currently Im running it without any overclocking at all.

Thanks!

[1715050609]

1715050609

[suryc]

Currently, I have 3 of them in a rig and I have found that they are not all made equal. They are each over-clocked at 1000-1040. Depending on your card and your cooling, it will have a different max where it is stable. You can easily adjust the settings in cgminer until you find the best settings for your particular setup.

Also, supposedly, you can undervolt to 1.087, but it depends on your Bios and Driver. I haven't been able to get it to work on my rig in Linux, but I have read where people using MSI Afterburner in Windows have been successful.

If you are using them for litecoin, Cryptobadger has a nice tutorial: http://www.cryptobadger.com/2013/04/build-a-litecoin-mining-rig-optimization/

[icebear888]

Thanks a stack!

It runs in a windows environment.

I use cgiminer though.

I will see what I can tweak in afterburner!

[ypsylon]

Yeap same here. While one easily sits on 480-490 MH/s out of the box rest struggle to reach 460 MH/s with seriously bumped core clock. Really baffling, but there you are. Default clock is 960/1250. Version for whole batch is 912-v276-032 r7950 tf 3GD5/OC BE. Built on reference 7950 PCB with 2 6pin PEG connectors. When underclocked memory sits on 800 MHz. I have primary, separate GTX580 which is not used for mining. In such setup memory can be underclocked even lower as mining VGA is not used to display content on the monitor.

Noise is deafening with fan running constantly over 3300-4000 rpm. Border line for silent operation is 2800 rpm, but it is impossible to mine BTC with such low fans. Temp just shuts up past 80++ in no time.

Weakest point of pretty much all 7950 (but MSI TF in particular) is cooling. With 80 mm fans there is simply no way of keeping the noise down with enough air pumped. I have one TF slapped with 3x120 Scythe 1200 fans 2 on top and 1 hanging on the edge pumping air under the shroud roughly where VRM section is located. This one is relatively quiet. Remaining TF mounted in classic tower case without any additional cooling make massive racket with fans constantly 3500+ and temp not exceeding 80 on core and 83 on VRM. My only question is who the hell thought that 80mm fans are good enough to cool VGA. My GTX580 is also MSI TF3, but with 120mm fans. It is brilliant, brilliant, sublime card, even when pushed to the absolute limit it is pretty much quiet with absolute negligible fan hum when loaded 100%.

Thinking about watercooling all miners, but cost is a bit prohibitive. Maybe I will slap Prolimatech's MK-26, with guaranteed drop of ~15C degrees it is cheap way of squeezing more MH/s with less noise.

[AvenG]

what do you guys think about Gigabyte's GPU? I'm considering purchasing it instead of MSI.. currently both cost the same on NewEgg.

[greaterninja]

what do you guys think about Gigabyte's GPU? I'm considering purchasing it instead of MSI.. currently both cost the same on NewEgg.

So far I have bought Powercolor, XFX, Gigabyte and Sapphire Radeons.


XFX is eh, OK.

Powercolor is decent for price but usually runs 10C hotter.  You have to downclock memory to run these cards in a rig.

Gigabyte is hit or miss:  1 good product, 2 bad products from newegg.


Sapphire has not let me down, ever...so far.  They OC well and stay 10C-15C ooler than my Powercolor cards.  I get more mhash/sec out of my 7950 sapphires than powercolor 7950s.

I hear MSI makes good twin frozer cards but have yet to actually test.

[Eric Rye]

...
Sapphire has not let me down, ever...so far.  They OC well and stay 10C-15C ooler than my Powercolor cards.  I get more mhash/sec out of my 7950 sapphires than powercolor 7950s.
...

+1 on all counts.

[icebear888]

Thanks for the interesting post guys ( I dont suppose girls do this stuff?

If I run my cards "hot" the power consumption goes through the roof!

[poohbah]

I run a dual MSI/Sapphire 7590 setup and I use several steps that seem to work pretty well for me, depending on heat in the room. All of these use memory at 625mhz/1.5v.

0.95v/950mhz
1.0v/1050mhz
1.012v/1070mhz  (can run second card at 1100mhz if desired, same voltage)

[kinitex]

Check the gpu comparison table in my sig, and hover your mouse over the hash rate for the MSI 7950 twin frozr OC edition. There are a few fantastic configs for this card.

[icebear888]

Thanks a stack!

I will have a look!

[tagged]

I have not found a way to undervolt this card in linux yet, anyone have a way?

[suryc]

I have not found a way to undervolt this card in linux yet, anyone have a way?

What software are you using. It is very easy to do in cgminer (assuming your bios allows it).
Just pass this tag when you run it:
--gpu-vddc 1.087
or whatever voltage you want if not 1.087

You can also do it through the menus once cgminer is running [G]PU Management >> [C]hange Settings >> (select card 0,1,2,3... +enter) >> [V]oltage >> (input voltage + enter)

[gregyoung14]

I have not found a way to undervolt this card in linux yet, anyone have a way?

if cgminer doesn't change it for you with the gpu vdc option then your next best bet is flashing the bios.