Lower voltage of Sapphire 7950 to reduce power (linux-usb)[firmware mod]

[induktor]

Hello
I finally manage to make usb flashdrives with xubuntu 12.04 LTS persistent storage, and run cgminer 3.1.1 perfectly stable in my three miners.

However, there is one thing that I cannot control, VRM voltage!, which I can do perfectly from windows using trixx, but I really, REALLY wanna get rid of the hard drive!

So after asking around and read a LOT, the short answer is: you cannot modify VRM voltage from linux.

damn!
as a short term solution, I downclocked my miners to 850 Mhz, so they will work at 1.125V (my sapphire's 7950 automatically switch to 1.125v when GPU clock is 850 or lower), that will give me 2.5Mh/W efficiency, I can live with that, for now.... but I want to lower to 1.050V

So start looking at the BIOS itself, in HEX, and I found the parameter section of the card, see this image, a segment of my Sapphire 7950 OC Boost 3G:


These numbers, starting with 10 54 69 01 are the operational parameters of GPU Speed, Mem speed and VRM voltage of all 5 presets.

for instance, the first line:
10 (identifier maybe?)
54 69 01 -> 01 69 54 == 92500  (925 Mhz) Engine, OC speed
48 E8 01 -> 01 E8 48 == 125000 (1250 Mhz) Memory Mhz
02 FF  (??) A pointer to a ram area for the voltage?, this card is NOT voltage locked.

as you can see in the red-highlighted area, there is the voltage section, they are in litte indian, so B6 03 is 03 B6 which means: 0.950V
and 20 03 is 03 20 which means: 0.800V, this are constants

Now the problem is the section 02 FF and 01 FF, those numbers don't make any sense, the literal value would be 65282 and 65281, they make no sense at all, unless.... they are pointers!, but pointers to where... to where the real values are.

so, anyone interested into this?

what do you think will happen if I replace 02 FF with a constant value, let's say 1A 04 , that would be: 1.050V a great value for mining!.

The reason I am asking this, it's because I would like to hear more educated opinions, before I destroy a perfectly healthy card hehe.
So if my math is wrong please tell me!.

Here are another cards: Sapphire 7950 FLEX Edition


Here again we see what looks like a pointer:
01 FF for the first profile (OC)
52 03 which is 0.850V
B6 03 which is 0.950V
01 FF again this, what the F#@% is it!

Here I compare my card (left) with another profile that they said it has a lower operational voltage (on the right):



same story here.
and finally, two VaporX one of 950Mhz and another of 850Mhz versions (left and right respectively):



remember that parameters ends at 6B 03, and the first parameter starts with the 10 (all hex of course)

Same as my card which has 925Mhz Boost, the 950Mhz version has 02 FF and 01 FF, where the 850Mhz version (non BOOST) has only 01 FF

Sorry I made this so long, I hope it is understandable, if not, please ask, I will gladly explain!
any comments? help?, ideas?. (once I gather enough information I will modify one of my cards and tested it, but I prefer some feedback before that)

thanks for reading

[1714971850]

1714971850

[1714971850]

1714971850

[philips]

Before hexediting you might consider just using a lower voltage 7950 BIOS (you can find at least one at 1.09V, which is pretty sufficient).

For hexediting part you might use this thread: https://bitcointalk.org/index.php?topic=207898.msg2176563#msg2176563

[induktor]

Before hexediting you might consider just using a lower voltage 7950 BIOS (you can find at least one at 1.09V, which is pretty sufficient).

For hexediting part you might use this thread: https://bitcointalk.org/index.php?topic=207898.msg2176563#msg2176563

Thank you Phillis!, actually the third image in my post, where is says:
Here I compare my card (left) with another profile that they said it has a lower operational voltage (on the right):

is the bios you have recommended in another thread for the sapphire 7950.
interesting post, there are people there that says that does change, and others than not, so there is not very clear what is going on
specially to those 01 FF and 02 FF values in the power profiles, still unclear.

will try the bios you recommended first, and I will post here, before hexedit
thanks!

[philips]

Well, in short:

I have 7970 cards with original BIOS at 1.17V. I wasn't able to hexedit the voltage down on them.
I am not saying is impossible, only saying that I could not do it. Maybe because what sveetsnelda said here: https://bitcointalk.org/index.php?topic=207898.msg2177876#msg2177876
Probably there are workarounds for it as described later in the same thread. OK.

So I took a 7950 BIOS which has the voltage already at a lower value of 1.09V and hexedit the memory (which is possible and rather easy this time) to a lower value.
I made two of them, one at 300 Mhz and one at 150 (the one I am using now).

If you want to have a look at them: BIOS 7950.zip

And please post if you find a method to alter the voltage.

[superfastkyle]

What cards do these work for? they don't work for reference 7950's, (ie sapphire 4l)

Well, in short:

I have 7970 cards with original BIOS at 1.17V. I wasn't able to hexedit the voltage down on them.
I am not saying is impossible, only saying that I could not do it. Maybe because what sveetsnelda said here: https://bitcointalk.org/index.php?topic=207898.msg2177876#msg2177876
Probably there are workarounds for it as described later in the same thread. OK.

So I took a 7950 BIOS which has the voltage already at a lower value of 1.09V and hexedit the memory (which is possible and rather easy this time) to a lower value.
I made two of them, one at 300 Mhz and one at 150 (the one I am using now).

If you want to have a look at them: BIOS 7950.zip

And please post if you find a method to alter the voltage.

[philips]

What cards do these work for? they don't work for reference 7950's, (ie sapphire 4l)

Cant say which cards will work or not. I took this 7950 BIOS from Techpowerup, and is the oldest and with the lowest clocks I could find.

All I can say for sure that it works on all of my 7970 cards: three Sapphire reference, one MSI and one XFX Double D. (some people around the forum reported that it works on their cards too)

What exactly do you mean by they don't work ? They don't boot or...?

Edit: you can try the BIOS edited by swordfish6975 : https://bitcointalk.org/index.php?topic=207898.msg2178230#msg2178230

[superfastkyle]

I figured it out no one send you had to add -f force parameter to get it to actually flash it

[philips]

Well, of course you need to use the force, Luke

[induktor]

Hello
I finally tried philips version, but didn't work with my three 7950 (all are exact model: Sapphire 7950 3G OC Boost 11196-16-20G )
So I decide to give it a try to your recommendation, download one by one the oldest versions from techpowerup and try, specially the ones with lower clock rate.

I found this one: http://www.techpowerup.com/vgabios/123785/sapphire-hd7950-3072-120330.html

that worked perfectly with my three cards.
Default clock is 810 Mhz at 1.090V, I was able to clock it up to 880 Mhz with cgminer in linux at the same voltage.
any higher and cgminer just set it to 880 Mhz, not more.

the cards are very stable, they generate less heat and the power consumption is 50W less than before.

so:
Before: 3x 7950 Stock fw, 850Mhz @ 1.125V -> 1.3 GH @ 550W
After: 3x 7950 120330 fw, 880Mhz @ 1.090V -> 1.4 GH @ 500W

I will love to be able to use it at 925 MHz but, I can't complain I'm having 2.8 MH/W which I think is very good ratio!.

will try the same with the other miner (4x 7850) to see if I can improve the 2.3 MH/W ratio that sucks.

BTW: I love the method for recovery the GPU from a bad flash, it's fantastic!.

[philips]

Hello
I finally tried philips version, but didn't work with my three 7950 (all are exact model: Sapphire 7950 3G

You mean the cards didn't accept the BIOS, or the flash went OK but the cards were bricked?

[induktor]

Hello
I finally tried philips version, but didn't work with my three 7950 (all are exact model: Sapphire 7950 3G

You mean the cards didn't accept the BIOS, or the flash went OK but the cards were bricked?

Sorry for my lack of accuracy, flash OK, but the cards where bricked, I always use the "force, luke" hehehe made me laugh my ass off with that one

With the version you are using, in linux can you go above 880Mhz in cgminer?

[philips]

I can go around 1110 Mhz.
They are 7970 (not 7950) but even for 7950 you can go past 1000 (with this BIOS, yes)

[induktor]

I can go around 1110 Mhz.
They are 7970 (not 7950) but even for 7950 you can go past 1000 (with this BIOS, yes)

1100MHz Wooha!
I will have to try another bios, anything above 880 Mhz just get "driver error" and returns to 880 MHz (I can lower it, no problem, but cannot go higher than 880 MHz.

EDIT: Just tested the very same bios with the two Sapphire 7950 3G FLEX Edition and they worked perfectly, 1.090V max 880MHz same as the OC Boost, but nice to know that the FLEX and the OC BOOST can use the same bios

[MrBilling]

Pretty sure I have the same cards as you.  I have these ones.

Sapphire Radeon HD 7950 3GB DDR5 HDMI/DVI-I/Dual Mini DisplayPort PCI-Express Graphics Card with Boost 21196-00-20G



I have tried a ton of 7950 BIOSs.  In my opinion the ones Phillips has are the best.

What are you mining?  BTC or LTC?

If you are mining LTC you need the 1.09 V BIOS that has the regular memclock.  Phillips will know which one I am talking about.

If you are mining BTC then you need the 1.09 V 300 memclock BIOS.  You could use the 150 memclock one but I think the 300 is better.


The 1.09 V one runs just as stable as the stock 1.25 V BIOS.   And I run them at 1115/1500 mining LTC.


The difference in power savings going from 1.25 V to 1.09 V is a lot.  On my 5 card BAMT rig it was like 350-400 W.  and they run 10 degrees or so cooler too.



And instead of using Trixx or Afterburner or whatever just use cgminer.  Either make a config file or just use the arguments when you start cgminer.

Like ./cgminer --scrypt --auto-fan --temp-target 70 --temp-overheat 80 --gpu-engine 1115 --gpu-memclock 1500.


The only reason I have found to have to use Trixx or whatever is if you are using Windows you can use one of them to either lower the V or lower the memclock.

[induktor]

Hello
Strange We have the same card, but I have tested the philip version, and my cards (none of them) boots with that version.

I only had sucess with the bios I mention (Sapphire.HD7950.3072.120330) from techpowerup.

I use cgminer under linux (boot from a usb persistent stick, xbubuntu 12.04) I made a dual config in xcfe, to mine LTC or BTC just by clicking an icon on the desktop and have the proper setups for each one.

So far I am using the 7970 for LTC and the 7950 for BTC (since, I think 7970 are more efficient in LTC than BTC work).
and yes the difference, running at 1.090V, in power consumption, is impressive!

I will try to do the same with the 7850 but so far haven't find any bios that allows me to operate lower than 1.050V, will keep looking

[micitzu]

Pretty sure I have the same cards as you.  I have these ones.

Sapphire Radeon HD 7950 3GB DDR5 HDMI/DVI-I/Dual Mini DisplayPort PCI-Express Graphics Card with Boost 21196-00-20G



I have tried a ton of 7950 BIOSs.  In my opinion the ones Phillips has are the best.

What are you mining?  BTC or LTC?

If you are mining LTC you need the 1.09 V BIOS that has the regular memclock.  Phillips will know which one I am talking about.

If you are mining BTC then you need the 1.09 V 300 memclock BIOS.  You could use the 150 memclock one but I think the 300 is better.


The 1.09 V one runs just as stable as the stock 1.25 V BIOS.   And I run them at 1115/1500 mining LTC.


The difference in power savings going from 1.25 V to 1.09 V is a lot.  On my 5 card BAMT rig it was like 350-400 W.  and they run 10 degrees or so cooler too.



And instead of using Trixx or Afterburner or whatever just use cgminer.  Either make a config file or just use the arguments when you start cgminer.

Like ./cgminer --scrypt --auto-fan --temp-target 70 --temp-overheat 80 --gpu-engine 1115 --gpu-memclock 1500.


The only reason I have found to have to use Trixx or whatever is if you are using Windows you can use one of them to either lower the V or lower the memclock.

Good day,

Can you please send me the firmware that you are using.

What cards are you using?

I am using Sapphire 7950 Vapor X 11196-09-40G - and at 1115 with 1500 the system is very unstable - many Hardware Errors (at 1 every 10 sec) in cgminer...

I need a firmware stable for mining LTC for this 11196-09-40G.

Thank you for your support in the matter,

[philips]

A new BIOS will not fix the HW errors you have. Most likely those are caused by a crappy driver.

[induktor]

or overclocking it too much 1115 yikes! way too high for my stomach

you should work on stability before try a different/modded bios, because it will probably make it more unstable than the original one.

yes lower voltage means less heat and less power consumption, but it also means that the card is a lot more unstable at high clock speeds.
I have one card that at 950 Mhz is already acting strange every now and then, actually running it a 925Mhz and it is fine, where the other ones has no problem at 950, and all are exact same model, however with the original bios, all cards can be clocked a lot higher without issues.

[suprabitz]

MrBilling which bios are you using for 1.09v and 1115/1500 on a sapphire? I'm confused about bios's I don't want a 300mhz memclock since i'm mining litecoins...

thanks

Pretty sure I have the same cards as you.  I have these ones.

Sapphire Radeon HD 7950 3GB DDR5 HDMI/DVI-I/Dual Mini DisplayPort PCI-Express Graphics Card with Boost 21196-00-20G



I have tried a ton of 7950 BIOSs.  In my opinion the ones Phillips has are the best.

What are you mining?  BTC or LTC?

If you are mining LTC you need the 1.09 V BIOS that has the regular memclock.  Phillips will know which one I am talking about.

If you are mining BTC then you need the 1.09 V 300 memclock BIOS.  You could use the 150 memclock one but I think the 300 is better.


The 1.09 V one runs just as stable as the stock 1.25 V BIOS.   And I run them at 1115/1500 mining LTC.


The difference in power savings going from 1.25 V to 1.09 V is a lot.  On my 5 card BAMT rig it was like 350-400 W.  and they run 10 degrees or so cooler too.



And instead of using Trixx or Afterburner or whatever just use cgminer.  Either make a config file or just use the arguments when you start cgminer.

Like ./cgminer --scrypt --auto-fan --temp-target 70 --temp-overheat 80 --gpu-engine 1115 --gpu-memclock 1500.


The only reason I have found to have to use Trixx or whatever is if you are using Windows you can use one of them to either lower the V or lower the memclock.