One way to undervolt R9 300 series cards by BIOS mod

[navydude]

I will see what happens. Will get the dump as soon as possible. Whats the best program to use for dumping sapphire cards?

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[bobben2]

I will see what happens. Will get the dump as soon as possible. Whats the best program to use for dumping sapphire cards?

Use atiflash to get the original bios of the card.  All AMD cards are the same in that respect.

atiflash -s 0 youroriginalbios.rom

or some name you choose.
This will read the bios of the card in slot 0 into that file.

Although it sounds like we have the same Sapphire card, I wont send you the roms for my card as the bioses might
be on different revision levels;  to be safe, a bios mod should be based of the card's original bios.

[navydude]

Ok. I will get it when i get off work. I hope all 12 of the cards are the same. I ordered them all from newegg only a week apart. I appreciate you doing this for me.

[Tacalt]

Are you able to change the Core or the Memory in the GPU tweek software such as MSI afterburner after your fixed voltage mod? 

[ldw-com]

Hi Eliovp,
So its a one byte signed value?  I.e. F0 = -16 decimal.  Then I have to muliply by 6.25 to get -100mV offset value
and voila?
If that is all then I've got it and thanks a lot!

-100 = F0 ---- 100 / 6.25 = 16, -16 in hex = F0
-150 = E8
-175 = E4

So yeah you're right

The offset you want, for example -50, devide 50 by 6.25, make your result negative, so -8, convert that to hex and you have your value

Again, if you're going to mod roms, be sure that the correct offset for core voltage and/or mem voltage is available.

If not, it's possible (in some cases) to add that yourself.

However, Due to adding those bytes:-

- you need to correct table length for VoltageObjectInfo.
- the pointer within VoltageObjectInfo to i2c programming data would need updating as well.
- you also then need to remove the same amount of empty bytes to make UEFI/GOP at right offset location.
- directory of data/command tables would need updating in ROM to correct offset pointers to the tables as they would have shifted.

So in other words, it's not "that" easy :p

Are you able to change the Core or the Memory in the GPU tweek software such as MSI afterburner after your fixed voltage mod? 

Yup, that's not a problem at all

[Tacalt]

What is the position of the memory voltage setting in the BIOS file. I am interested in changing that.

[Eliovp]

What is the position of the memory voltage setting in the BIOS file. I am interested in changing that.

open your rom with atomicbiosreader, you can find the offset location for the voltage settings in the .txt file that gets generated.

you'll have to watch out though, not every rom has these values, my nano roms didn't have them, i had to add them myself.

[Boathouse]

Do you have a link to atomicbiosreader? I am interested in trying mod my XFX BIOS of the 1050 MHz black edition.

[Docnaster]

How much power does not memory consume when doing Ethereum at 1500 MHz? If it is over 30W, then it is better to under volt it.

[bobben2]

Do you have a link to atomicbiosreader? I am interested in trying mod my XFX BIOS of the 1050 MHz black edition.

Hi Boathouse
You can find a link to the atombios reader here

http://www.overclock.net/t/1561372/lightbox/post/24069731/id/2549733

Look for the AtomBiosReader section.

[bobben2]

Hi Eliovp,
So its a one byte signed value?  I.e. F0 = -16 decimal.  Then I have to muliply by 6.25 to get -100mV offset value
and voila?
If that is all then I've got it and thanks a lot!

-100 = F0 ---- 100 / 6.25 = 16, -16 in hex = F0
-150 = E8
-175 = E4

So yeah you're right

The offset you want, for example -50, devide 50 by 6.25, make your result negative, so -8, convert that to hex and you have your value

Again, if you're going to mod roms, be sure that the correct offset for core voltage and/or mem voltage is available.

If not, it's possible (in some cases) to add that yourself.

However, Due to adding those bytes:-

- you need to correct table length for VoltageObjectInfo.
- the pointer within VoltageObjectInfo to i2c programming data would need updating as well.
- you also then need to remove the same amount of empty bytes to make UEFI/GOP at right offset location.
- directory of data/command tables would need updating in ROM to correct offset pointers to the tables as they would have shifted.

So in other words, it's not "that" easy :p

Are you able to change the Core or the Memory in the GPU tweek software such as MSI afterburner after your fixed voltage mod?  

Yup, that's not a problem at all

So I first need to find the location of the VoltageObjectInfo.
To search for the start and length of the VoltageObjectInfo table I figure I need to locate the position of the following pattern: xx 00 03 01 01 03
where xx is the length in bytes of that table?  (obviously omitting xx in the search pattern)
And then to see if I have a voltage offset entry, look for pattern 8d 00 xx 00 (omitting xx which is the actual voltage offset value)
within the VoltageObjectInfo table. Correct?

[Eliovp]

So I first need to find the location of the VoltageObjectInfo.
To search for the start and length of the VoltageObjectInfo table I figure I need to locate the position of the following pattern: xx 00 03 01 01 03
where xx is the length in bytes of that table?  (obviously omitting xx in the search pattern)
And then to see if I have a voltage offset entry, look for pattern 8d 00 xx 00 (omitting xx which is the actual voltage offset value)
within the VoltageObjectInfo table. Correct?

Atomic output will give you the offset location. It's all there , just open HxD and hit search, enter the offset there and it'll point you to the exact point

If 8D 00 xx 00 isn't there, that means that "or it just isn't possible to mod, or you need to add that yourself", keep in mind, it's not just adding it into the rom, you'd have to follow some other steps to complete that process (as i stated before)

- you need to correct table length for VoltageObjectInfo.
- the pointer within VoltageObjectInfo to i2c programming data would need updating as well.
- you also then need to remove the same amount of empty bytes to make UEFI/GOP at right offset location.
- directory of data/command tables would need updating in ROM to correct offset pointers to the tables as they would have shifted.

If it's there, then you just need to edit "xx" as i told you before
If 8E is also there (is always right behind 8D) then you can also mod the memory voltage given to the controller.

Greetings!

[Hutalar]

Eliovp, I had a look at the XFX 1015MHz BIOS you mod for Marvel. I search edfor the 8d 00 xx 00, I could not find that. Did you mod the Core or the memory voltage?

I remember you said both -100 mV for Core and memory.

[Eliovp]

Eliovp, I had a look at the XFX 1015MHz BIOS you mod for Marvel. I search edfor the 8d 00 xx 00, I could not find that. Did you mod the Core or the memory voltage?

I remember you said both -100 mV for Core and memory.

I didn't add those values, i only changed the DPM states.

Looking back at those, i will report back with a new one next week because it seems that i failed miserably on that one "XFX 390 for Marvel".

Greetings

[gupsterg]

However, Due to adding those bytes:-

- you need to correct table length for VoltageObjectInfo.
- the pointer within VoltageObjectInfo to i2c programming data would need updating as well.
- you also then need to remove the same amount of empty bytes to make UEFI/GOP at right offset location.
- directory of data/command tables would need updating in ROM to correct offset pointers to the tables as they would have shifted.

WOW, I'm thinking these are my words  .

[ldw-com]

However, Due to adding those bytes:-

- you need to correct table length for VoltageObjectInfo.
- the pointer within VoltageObjectInfo to i2c programming data would need updating as well.
- you also then need to remove the same amount of empty bytes to make UEFI/GOP at right offset location.
- directory of data/command tables would need updating in ROM to correct offset pointers to the tables as they would have shifted.

WOW, I'm thinking these are my words  .

haha, they are!

[gupsterg]

All good mate  , I lurk here on and off and hadn't been here in a while. Then when I saw this and didn't recognise user name I thought I'd been hacked  .

[playjho]

Hello there, I followed the instructions of the op to undervolt my Gigabyte r9 390, but when I read the voltage values in the gpu freq table here is what I got :

0   0xA49D   300   Mhz   24-bit   0xA4A0   900
1   0xA4A2   525   Mhz   24-bit   0xA4A5   65282
2   0xA4A7   723   Mhz   24-bit   0xA4AA   65283
3   0xA4AC   883   Mhz   24-bit   0xA4AF   65284
4   0xA4B1   924   Mhz   24-bit   0xA4B4   65285
5   0xA4B6   960   Mhz   24-bit   0xA4B9   65286
6   0xA4BB   994   Mhz   24-bit   0xA4BE   65287
7   0xA4C0   1025   Mhz   24-bit   0xA4C3   65288


As you can see, excepting state 0, the other state voltages are not what I was waiting for.

Do you think it's safe to try values comparable to the values of the op ?

[Zistmine]

Hello there, I followed the instructions of the op to undervolt my Gigabyte r9 390, but when I read the voltage values in the gpu freq table here is what I got :

0   0xA49D   300   Mhz   24-bit   0xA4A0   900
1   0xA4A2   525   Mhz   24-bit   0xA4A5   65282
2   0xA4A7   723   Mhz   24-bit   0xA4AA   65283
3   0xA4AC   883   Mhz   24-bit   0xA4AF   65284
4   0xA4B1   924   Mhz   24-bit   0xA4B4   65285
5   0xA4B6   960   Mhz   24-bit   0xA4B9   65286
6   0xA4BB   994   Mhz   24-bit   0xA4BE   65287
7   0xA4C0   1025   Mhz   24-bit   0xA4C3   65288


As you can see, excepting state 0, the other state voltages are not what I was waiting for.

Do you think it's safe to try values comparable to the values of the op ?

It is very safe to do. For my XFX 1015 MHz, I use the similar voltage as the OP, but is generally lower.

OP is left mine right.

1000  800
1000  825
1050  850
1050  900
1100  950
1100  975
1100 1000
1106 1050

[Eliovp]

Hello there, I followed the instructions of the op to undervolt my Gigabyte r9 390, but when I read the voltage values in the gpu freq table here is what I got :

0   0xA49D   300   Mhz   24-bit   0xA4A0   900
1   0xA4A2   525   Mhz   24-bit   0xA4A5   65282
2   0xA4A7   723   Mhz   24-bit   0xA4AA   65283
3   0xA4AC   883   Mhz   24-bit   0xA4AF   65284
4   0xA4B1   924   Mhz   24-bit   0xA4B4   65285
5   0xA4B6   960   Mhz   24-bit   0xA4B9   65286
6   0xA4BB   994   Mhz   24-bit   0xA4BE   65287
7   0xA4C0   1025   Mhz   24-bit   0xA4C3   65288


As you can see, excepting state 0, the other state voltages are not what I was waiting for.

Do you think it's safe to try values comparable to the values of the op ?

It is very safe to do. For my XFX 1015 MHz, I use the similar voltage as the OP, but is generally lower.

OP is left mine right.

1000  800
1000  825
1050  850
1050  900
1100  950
1100  975
1100 1000
1106 1050

Yup, should be good!

In the example given here, you give the DPM's a fixed state. It'll do the trick!

Just be careful though, it could be that 1.05v is not enough power to handle 1025 core clock. All depends on your gpu.