Vmod 3850 through BIOS apparently IS possible....

[Bo_Fox]

Wow that was quick.. are you really sure that it will work? There is still 1 instance of 1.214v in there and 5 instances of 1.014v for low-power 2D.

I'm real nervous because I've never flashed a GPU BIOS before!!! I've done hardware volt-modding on my 9800Pro 3 years ago and that was it...

[Bo_Fox]

attached,
his3850-512@735/1960, voltmoded 2d@1.24 / 3D@1.33v
i have tested it with atiflash, atiwinflash doesnt work for me.

Also, thank you.

[spectrum48]

attached,
his3850-512@735/1960, voltmoded 2d@1.24 / 3D@1.33v
i have tested it with atiflash, atiwinflash doesnt work for me.

can you please mod my bios with 1.33v 3d?
i don't really care about changing the clocks, but if it's not too much trouble make it @ 750/950

thanx

[Eldonko]

can you please mod my bios with 1.33v 3d?
i don't really care about changing the clocks, but if it's not too much trouble make it @ 750/950

thanx

Yah I could use that too!

[Bo_Fox]

I just did a hex compare and it looks great.. but I edited the checksum part so that it has the exact same checksum and I wont have to "force" flash.

Off to flashing.. be back shortly, with my fingers crossed!!!!!

[Chukundur]

Gigabyte 3850 1.37V Load (1.289V form BIOS, 1.63KOhm vGPU Mod), 1.04 Idle. Accelero S1 + 2x92mm Arctic cooling 12V 1.0A very quiet.

[Bo_Fox]

YES, it works!!!!!! THANK YOU SO MUCH, the-strokes and everybody else who provided useful info. on the forums!

Now my IceQ3 card can do 836 Mhz artifact-free in ATiTool and 800 MHz stable so far in games.

IMHO, the quickest way to test true stability of your card is to start Quake 3 and enter console mode by pressing ~ (tilde) and then type timedemo 1. That will remove the 90fps cap but make sure you have Vsync disabled. With the latest Q3 patch, it will also utilize two CPU's at exactly 100% load each. My GPU is also being loaded at 99.99% at an average of 850fps. You can see the red transparent textures sliding over each other -- and you would easily be able to detect artifacts.

Also, another hint is to disable ATI VPU recover! If the card detects any core artifacting within games (doesn't apply for ATiTool as well), it will just crash or mess up your system. If it's o/c'ed way too high, just let it reboot anyway.

Quake 3, press ~ then type timedemo1 and do nothing for 5+ minutes (Vsync must be disabled)--
ONE OF THE QUICKEST STABILITY TESTS FOR YOUR GPU!!!

So, if you have that old Q3 game laying around or installed in your rig, you can still make very good use out of it.. so far, no other game have tested my GPU stability as quickly!!! If it could do 10-15 minutes of that, then you can be 98% sure that it will be perfectly stable for any other games--Crysis included. If it's just a tiny bit over the limit, Q3 will instantly crash in less than 2 minutes while I could do 3DMark06 or Lost Planet loops over and over...

[jimmyz]

OK, this is the last one, if it doesn't work, then i dont' know what else to do .

@Chuk
I hard volt-modded to get past 800, not using a volt-modded BIOS!


EDIT: stroke, i fixed the checksum for you, check if it will work, the checksum is for the 256 version, but i noticed that even if you set it for 3870 it will still work, as long as it's a known card it seems!

there you go, now it works , not to nit pick but ha anyone figured out why ccc overdrive won't work with these bios's? with the one denny posted i was able to clock up to 900 the modded bios's top at 730? there must be some section of the bios which tells overdrive what the speed is.

the reason i need a high core is that is the easiest way to clock second card. when i had denny's bios it allowed 900 but was a .67 bios with max at 865mhz. both of my cards are v-modded and watercooled and I need to be able to clock to 1000. so far riva maxes for me at 999 actual and either card can do that, just cannot do it in crossfire

[tarkin77]

I have an GeCube Radeon HD 3850 X-Turbo III ... can I use this modified HIS bios or do I need a modded bios version of my own card?

[Bo_Fox]

Hold on, I'll upload mine with fixed checksum in a few minutes... works perfectly fine in all games and benchmarks (gave me a 50 Mhz boost on core) thanks to 3870 voltage.

[robbot]

ok we are waiting....

witch card do you have ?

[os008]

anyone figured out why ccc overdrive won't work with these bios's? with the one denny posted i was able to clock up to 900 the modded bios's top at 730? there must be some section of the bios which tells overdrive what the speed is.

Can you please point at the post that he posted that BIOS, i'll compare it to the original and try to figure out the differences, cause i also want to know how to get Overdrive to work with a modded BIOS!

[the-strokes]

os008, bo_fox, spectrum : thx for sharing ur bios..

heres sapphire 3850 512, 2D@1,24, 3D @1,33..cheksum's already equal.
didnt change the clocks, u can try to modifiy them if u like, 0s008 have the guide and tools for bios mod here

[Bo_Fox]

Can you please point at the post that he posted that BIOS, i'll compare it to the original and try to figure out the differences, cause i also want to know how to get Overdrive to work with a modded BIOS!

I think it is due to the voltage-lookup tables that ATI uses with the 38xx series (that's why voltage cannot be changed as easily in software like with X19xx series). I heard that when overclocking, Overdrive slightly bumps the voltage by miniscule amounts that hardly help at all, like by 0.005v increments or something like that (cant remember where I got the info..). For all 3850 cards, there is a specific voltage to be expected by the drivers and if they do not match, it wont work, as I have recently confirmed.

However, Rivatuner still works with overclocking, which is a big .

With HIS default bios, CCC allows me to slide it all the way to 900 MHz core and insane memory speeds. So here it is again, with a different filename this time.. It "should" be overclockable using CCC since this bios is default and unchanged. Also, the official speed in the hex editor is 736/982, not 735/980.

Description:
HIS Radeon HD 3850 IceQ3 TurboX 512MB 736/982 default clocks
ATI's CCC sliders maximum of 900MHz core and 1100 MHz memory
DEFAULT BIOS

[Bo_Fox]

And here is the modded bios from the same one in my last post, but with 3870 voltages. It is the same as the one that the-strokes edited for me, but I fixed the checksum so that it's exactly the same as default (no need to 'force' flash).

(Keep in mind that it does not allow for overclocking within CCC but can be overclocked just fine using Rivatuner). This one gave me a 50Mhz stable core boost over the default one.

Description:
HIS Radeon HD 3850 IceQ3 TurboX 512MB 736/982 default clocks
MODDED BIOS WITH 3870 voltage (2-D: 1.241v, 3-D: 1.327v)

[spectrum48]

os008, bo_fox, spectrum : thx for sharing ur bios..

heres sapphire 3850 512, 2D@1,24, 3D @1,33..cheksum's already equal.
didnt change the clocks, u can try to modifiy them if u like, 0s008 have the guide and tools for bios mod here

i can't thank you enough mate

i'm going to try and test it now

[spectrum48]

no go mate, the multimeter still says 1.22v 3d

also 0s088's guide doesn't explain anything, just gives examples
for instance, how do i know which are the values for mem clocks and how many of these values shoul i change

[spectrum48]

edited: i'm an idiot and in need of sleep, sorry for the spam

[os008]

With HIS default bios, CCC allows me to slide it all the way to 900 MHz core and insane memory speeds. So here it is again, with a different filename this time..

I found the part that changes the Overdrive limits, when i changed it, CCC didn't recognise my card, as if i didn't install a driver!

[spectrum48]

anyone know why atiwinflash doesn't want to flash the mod bios?

i load the file, but it says 'VBIOS image not found'

i tried renaming it, i even made a copy with the new voltages myself but it won't flash it

[Eldonko]

Use atiflash from USB drive, I cant get aitwinflash to work either.

[jimmyz]

Use atiflash from USB drive, I cant get aitwinflash to work either.

works perfect for me. but i don't force flash so the bios needs to be compatible or i get the same message

[eva2000]

Wow haven't checked up on 3850 related bios info and see all that has been happening here...

question can you change the default fan speed from bios on 512mb HD3850s ?

[Eldonko]

heres sapphire 3850 512, 2D@1,24, 3D @1,33..cheksum's already equal.
didnt change the clocks, u can try to modifiy them if u like, 0s008 have the guide and tools for bios mod here

Got me 32 extra Mhz on core, thanks!

[Chukundur]

There is no senese for using 1.24V for 300MHz in 2D. It's much better to use 0.974V for lower temp in Idle.