Bitcoin Forum
June 14, 2024, 08:23:14 AM *
News: Latest Bitcoin Core release: 27.0 [Torrent]
 
   Home   Help Search Login Register More  
Pages: [1]
  Print  
Author Topic: 7970 BAMT UNDERVOLT - pls Help  (Read 5407 times)
lastbit (OP)
Full Member
***
Offline Offline

Activity: 206
Merit: 100


View Profile
March 09, 2013, 10:25:03 AM
 #1

It seems that, although it's simple in Windows w/ Afterburner, you cannot UNDERVOLT under BAMT/Linux. I mean you can, but it's not applied, even if it's reported as applied, neither with atitweak, neither with cgminer.
I mean you can undervolt, but it's useless because there are some frequency thresholds and if you set frequency greater than threshold for a voltage, voltage automatically goes to the next respective voltage. The thresholds are:
    0.85V -> 450MHz
    0.90V -> 600MHz
    0.95V -> 700MHz
    nominal voltage -> unlimited frequency to at least 1210MHz (I could not try more).
I'm pretty sure about this behavious, I have tested with both GPU-Z under Windows, and voltmeter on GPU voltage rail and clampmeter on video card power supply wires under Linux.
To add insult to injury, you cannot modify the BIOS, it seems there's a checksum nobody knows how to compute.

Now, why I would want to undervolt? Lets say I'm able to undervolt 10%. I'll loose around 10% maximum frequency (hashing rate). But I'll made around 30% power savings (21% from voltage drop, 10% from frequency). So, with only 10% lower hashing rate, 30% power savings, and much lower noise.

But there might be a way. It looks like 7970 nominal voltage can be one of the following:
    1.175V = ASIQ quality <75
    1.112V = ASIQ quality between 75 and 80
    1.050V = ASIQ quality between 80 and 85
    1.025V = ASIQ quality between 85 and 90
So, in theory, if you write a 1.025V BIOS on a 1.112V card and it works, like I want to do, you'll make a 8% undervolt.

Can somebody help me with a 1.025V BIOS for MSI R7970-2PMD3GD5?
(on www.techpowerup.com there's only one BIOS for my card Sad )

In Windows, ASIC quality can be obtained with right click on GPU-Z title bar. BIOS can be dumped from GPU-Z also.
Gator-hex
Hero Member
*****
Offline Offline

Activity: 490
Merit: 500


View Profile
March 13, 2013, 07:56:53 PM
 #2

Silly question but did you try rebooting after saving your settings?
Some things on Linux don't get applied until the boot scripts run.
Can be a bit of a hassle if you underclock it enough to stop it rebooting though.  Roll Eyes

-ck
Legendary
*
Offline Offline

Activity: 4144
Merit: 1637


Ruu \o/


View Profile WWW
March 13, 2013, 11:17:56 PM
Last edit: March 15, 2013, 04:06:08 AM by ckolivas
 #3

Silly question but did you try rebooting after saving your settings?
Some things on Linux don't get applied until the boot scripts run.
Can be a bit of a hassle if you underclock it enough to stop it rebooting though.  Roll Eyes
You cannot directly software undervolt 7970s on linux.

Developer/maintainer for cgminer, ckpool/ckproxy, and the -ck kernel
2% Fee Solo mining at solo.ckpool.org
-ck
jdat
Newbie
*
Offline Offline

Activity: 33
Merit: 0



View Profile
March 14, 2013, 10:08:34 PM
 #4

You may undervolt on windows, and then reboot to linux. I think as long as power doesn't go off, it will keep the setting.
lastbit (OP)
Full Member
***
Offline Offline

Activity: 206
Merit: 100


View Profile
March 15, 2013, 12:28:16 AM
 #5

I succeeded in undervolting on linux/bamt.  Grin Grin Grin Grin
I running now with 7970 at ~4.8Mh/J on reduced voltage versus ~3.2Mh/J on stock voltage.  Grin Grin Grin Grin
I'll make next week a separate thread in case somebody's interested.
lastbit (OP)
Full Member
***
Offline Offline

Activity: 206
Merit: 100


View Profile
March 15, 2013, 12:30:11 AM
 #6

You may undervolt on windows, and then reboot to linux. I think as long as power doesn't go off, it will keep the setting.
Although I haven't tried I believe you're right... but it's too much complicated if you have many rigs.
jdat
Newbie
*
Offline Offline

Activity: 33
Merit: 0



View Profile
March 15, 2013, 01:28:14 AM
 #7

Great! I'm curious, how did you do that? I hope it wasn't afterburner with wine..  Tongue
goxed
Legendary
*
Offline Offline

Activity: 1946
Merit: 1006


Bitcoin / Crypto mining Hardware.


View Profile
March 15, 2013, 01:34:07 AM
 #8

I succeeded in undervolting on linux/bamt.  Grin Grin Grin Grin
I running now with 7970 at ~4.8Mh/J on reduced voltage versus ~3.2Mh/J on stock voltage.  Grin Grin Grin Grin
I'll make next week a separate thread in case somebody's interested.

yeah very curious. how did u manage to uv on Linux.

Revewing Bitcoin / Crypto mining Hardware.
lastbit (OP)
Full Member
***
Offline Offline

Activity: 206
Merit: 100


View Profile
March 15, 2013, 02:53:06 AM
 #9

I have modified the BIOS, but... it is not straightforward Smiley
goxed
Legendary
*
Offline Offline

Activity: 1946
Merit: 1006


Bitcoin / Crypto mining Hardware.


View Profile
March 15, 2013, 04:29:16 AM
 #10

I have modified the BIOS, but... it is not straightforward Smiley
hmm, did u digitally sign the bios? I have tried umpteen times to obtain lower voltage bios from powercolor support, but no fish.

Revewing Bitcoin / Crypto mining Hardware.
lastbit (OP)
Full Member
***
Offline Offline

Activity: 206
Merit: 100


View Profile
March 15, 2013, 09:32:23 AM
 #11

I have obtained only one point of undervolting (obtaining ~540 Mh/s at ~110W) and I have to work a little more to see how much I can extend my ideea. I'll post again in a few days when I'll finish.
goxed
Legendary
*
Offline Offline

Activity: 1946
Merit: 1006


Bitcoin / Crypto mining Hardware.


View Profile
March 15, 2013, 10:21:38 PM
 #12

I have obtained only one point of undervolting (obtaining ~540 Mh/s at ~110W) and I have to work a little more to see how much I can extend my ideea. I'll post again in a few days when I'll finish.

waiting. good luck!

Revewing Bitcoin / Crypto mining Hardware.
drakoin
Hero Member
*****
Offline Offline

Activity: 826
Merit: 1000

see my profile


View Profile
December 30, 2013, 02:48:20 AM
 #13

I'll post again in a few days when I'll finish.

yes, please, inform us :-)


I have:
1 PowerColor HD 7850 (AX7850 2GBD5-DH) 85.3% ASIC quality
1 XFX R7970 DD (FX-797A-TDFC) 68.6% ASIC quality

what to do to undervolt?

no sign of a signature
drakoin
Hero Member
*****
Offline Offline

Activity: 826
Merit: 1000

see my profile


View Profile
January 01, 2014, 10:46:14 PM
 #14

I'll post again in a few days when I'll finish.
what was your result?


threads about my undervolting questions:

no sign of a signature
drakoin
Hero Member
*****
Offline Offline

Activity: 826
Merit: 1000

see my profile


View Profile
January 03, 2014, 04:33:24 AM
 #15

I just want to announce SUCCESS :-) I did it!
Undervolting XFX 7970 DD by tweaking the original BIOS;
amazing results, saving 1/3 energy!

Instructions here:
https://bitcointalk.org/index.php?topic=395004.msg4282261#msg4282261

 Cool


no sign of a signature
Pages: [1]
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.19 | SMF © 2006-2009, Simple Machines Valid XHTML 1.0! Valid CSS!