Vmod 3850 through BIOS apparently IS possible....

[302 Stang]

with the sapphire 3850 512mb, CCC hardly allow any oc at all (720/950 lock).

is this a lock in the bios?

I found this, so I guess it is..


is there anyone who have edited these values? and what is BE 04 doing there again? I compared the sapphire bios to a HIS oc and it is basically the same apart from the clock speeds.

I know riva works, Im just curious.

[sheikoso]

Could someone please mod my bios to 1.33V? i cant pass 770/950...


thanks.. =)

[ralf11]

with the sapphire 3850 512mb, CCC hardly allow any oc at all (720/950 lock).

is this a lock in the bios?

I found this, so I guess it is..


is there anyone who have edited these values? and what is BE 04 doing there again? I compared the sapphire bios to a HIS oc and it is basically the same apart from the clock speeds.

I know riva works, Im just curious.

If change this value in bios, computer cant see my graphics card

[302 Stang]

If change this value in bios, computer cant see my graphics card

ok, even if checksum is correct?

[ralf11]

ok, even if checksum is correct?

how make checksum correct in bios??.

[302 Stang]

how make checksum correct in bios??.

its explained earlier in this thread http://www.xtremesystems.org/forums/...9&postcount=65

edit: without correct checksum I dont get any device id and screen goes black.

edit2: didn't help... Driver says "no valid ati device" maybe should have tried to reinstall?

[robbot]

Can somebody modify bios for HD 3850 256MB

385/ 925 with changed only 3d voltage

thx a lot

[ralf11]

Reinstall drivers dont work. System still dont see graphics card.

[RaiderX303]

can someone modify this to 1.33v and increase the default clocks to 730/2000 thanks.

[Hola77]

Hello people, I'm new here at extremesystems. Been waiting for like 2 weeks to get permission to start posting. I need you experts to unleash my card which has given me a lot of sorrow.
I have a Gigabyte 3850 512mb (ultra durable 2). The problem is that it has a different PCB compared to the standard one and runs at lower memory speeds aswell (700Mhz). So I tried a pencilmod by reading some threads, but it didn't work because of the different layout of the PCB.
Now what really drives me insane is the different BIOS it uses. It prevents me from using any of the modded BIOSes.
I would like to ask if someone could take a look a my BIOS and raise the voltage to 3870 levels. It hasn't been done yet for this card and there are more people around the world who are aching to get a modded bios for it.
So please anyone who feels up to it, take a shot. It would be the first modded BIOS of it's kind I guess.

[302 Stang]

Its not that hard.. Just that I dont want to be responsible för anyones dead 38xx

its explained on the first page of this tread

example pic


hex editor
http://mh-nexus.de/downloads/HxDen.zip

checksum fix is also explained

[sheikoso]

but if the card dies, can i recover by another vga card in pci slot (only for boot the pc)?.

[302 Stang]

Dont know how bad you can screw up the card with a faulty bios???
Otherwise, yes. Or you can do it blindly.

[Hola77]

Its not that hard.. Just that I dont want to be responsible för anyones dead 38xx

its explained on the first page of this tread

example pic


hex editor
http://mh-nexus.de/downloads/HxDen.zip

checksum fix is also explained

Thanks for your input! I've done it!
I was hoping for more than 1,28v, but this limit seems to be the same as on the other 3850 models. It runs at 800Mhz now, I was doing 756 before.
I was getting a black screen at first, had to fix the checksum
Although I don't understand why it won't allow more voltage. It has exactly the same PCB as the 3870 model from Gigabyte. Only the memory is different.
Anyways, thanks again.


Here it is for download (Gigabyte 3850 512MB BIOS):

[eddieobscurant]

Could someone please explain to me how to fix the checksum. I've read the previous pages but i couldn't fully understand. I attach you the original bios and the modded bios (changed 3d gpu clocks, mem clocks and voltage {750/2000 1.33volt}) but I get a blank screen after reboot. I think I've done it everything right except from the checksum that I don't know how to fix it.
If someone could explain to me how to fix it, or fix it by himself, I would be grateful.
My card is a sapphire 3850 512mb with quimonda memory.

You can download the original file from here http://www.megafileupload.com/en/fil...GINAL-rar.html

and the modded file from here http://www.megafileupload.com/en/fil...ODDED-rar.html

[maxmaz]

First of all, thanks to all people who have contributed to this thread. Using the provided info, I have modified my VisionTek HD3850 256MB bios to 810/1030 (1.33v) and have been enjoying it since a while ago.

Now for your checksum issue, it's very easy to fix:

Open your UNMODIFIED ORIGINAL bios in HexEditor. Click on "Analysis" and then "Checksums/digests..." and chose "Checksum-16" and click ok. Write down the value (which will be "5F00" in your case).

Now repeat the same thing with your modified new bios and write down the new checksum value (which is "5774" in your case).

The whole issue of fixing the checksum is just about doing additional changes in the file, so that the checksum value of the modified file is equal to the checksum of the original file. In your case, you have to increase it from 5774 to 5F00 (we are obviously talking about numbers here... hex not decimal, but numbers nonetheless, right?) So, you have to add values somewhere in the modified bios to make the checksum increase. In order to avoid messing up with the file, people have used the message area right on top of the bios (... YOU HAVE NOT CONNECTED THE POWER CABLE TO YOUR VIDEO CARD.PLEASE...) since this is just a warning message and changing its content is not going to affect anything. If you check other modified files, most people have changed around the "VIDEO" word. So, go to the value right before the "VIDEO" and click there and change the first number to "F" (remember that we want to increase the checksum and "F" is the biggest single digit value in hex just as "9" is the biggest in decimal). Repeat the steps above and get the checksum. If it's still smaller than your original checksum value, continue with changing next numbers to F up to the point that you exceed your original checksum and then, start changing the last digit to smaller values (e.g. if changing the last value to "F" resulted in your new checksum being "5F03" which is bigger than the original value of "5F00", change the last "F" to "C" and so forth so that the new checksum is exactly equal to the original one. Save it, flash your card with it and enjoy!

Of course, here in your case, we have to increase the checksum value to reach the original. If the modified bios has a checksum greater than the original one, it is exactly the same, but this time you want to change values one-by-one to "0" instead of "F" to make it smaller...

Hope it helps!

[eddieobscurant]

Thank you very much my friend. I really, really , really thank you. I have spent many days trying to figure out how to use a hex editor at first cause all the bios that i had downloaded didn't work for me. And when i did, i had a blank screen cause i didn't know what was the problem (checksum). Finally everything is ok. Again, thank you very much.

[CapFTP]

Thank you very much my friend. I really, really , really thank you. I have spent many days trying to figure out how to use a hex editor at first cause all the bios that i had downloaded didn't work for me. And when i did, i had a blank screen cause i didn't know what was the problem (checksum). Finally everything is ok. Again, thank you very much.

yes !!! absolutely many thnx also from my side !.....really well xplained !

[maxmaz]

You're most welcome guys! Now it's your turn to share the knowledge if anyone needed help.

All the best!

[Barr3l Rid3r]

What about Gigabyte HD3870 512MB DDR3? It uses Qimonda DDR3 memory chips, and the bios should be a solution for locked 3850 512MB eighter.

I can post this bios very soon, just need to know if Qimonda is a thrusty brand of chips to go.

[Hola77]

What about Gigabyte HD3870 512MB DDR3? It uses Qimonda DDR3 memory chips, and the bios should be a solution for locked 3850 512MB eighter.

I can post this bios very soon, just need to know if Qimonda is a thrusty brand of chips to go.

I already tried the Gigabyte 3870 bios on my Gigabyte 3850 512mb. Doesn't work though. The picture I got was all scrambled. Maybe I should have waited to load windows, but I didn't.
The cards have the same PCB, exept for one tiny chip on the back side. The 3850 has 2 of those chips, but the 3870 has 3. The spot of the third is empty on the 3850 board. And the DDR3 memory is also different. 3850 has hynix.

[Barr3l Rid3r]

I already tried the Gigabyte 3870 bios on my Gigabyte 3850 512mb. Doesn't work though. The picture I got was all scrambled. Maybe I should have waited to load windows, but I didn't.
The cards have the same PCB, exept for one tiny chip on the back side. The 3850 has 2 of those chips, but the 3870 has 3. The spot of the third is empty on the 3850 board. And the DDR3 memory is also different. 3850 has hynix.

Does anybody have an unlocked bios for Qimonda 3850?

Did u figure out how to make vgpu on it?

[Hola77]

Yes I did. I posted the modified bios on this page.

[CapFTP]

guys,,,,is there a way or a section to mod the fan speed ????

[d50man]

my gigabyte 3850 512mb has hynix memory on it

i pm'ed hola but never got a reply.