Here is the necessary:
1. Latest version of atiflash program.
It is used to “load” BIOS file from card and to flash edited bios.
2. Any hex editor
It is used to change certain HEX values in BIOS
Make bootable USB disk with ATI flash on it. After booting, start the ATI flash using command "atiflash -s 0 bios.rom"
Go back to Windows and load the bios.rom
Open the Overdrive section in Catalyst CC and look for def. clock values for 3D ( it is usual 667Mhz). In BIOS everything is written in HEX + backward. Frequency values are written with 5 characters (before HEX interpretation), and voltage values are written with 4 characters.
For example 669Mhz as 66900, 1150Mhz as 11500, and voltage 1.21V as 1210.
Open the base converter in HEX editor (if you use this editor), or you can use Win calc. Enter the 66900 in calc and (we are looking for 3D GPU value in BIOS) and convert it to HEX (we need 3 pairs of two caracters).
66900 (dec) -> 01 05 54 (hex)
Now we are looking for inverted HEX value in BIOS. We are looking for 54 05 01 (i.e. 669Mhz).
In ASUS 3850 256MB BIOS it is located at address AAE8 (just behind the memory speed value) – we are not interested in this row (if you change any of those two values, catalyst will no longer recognize the VGA, it will be standard VGA), and in this table, little lower, at address ADBF to AE4F. MEM speed value is just beside GPU speed value, followed by GPU voltage value.
Here is how it looks in HEX editor
http://img146.imageshack.us/img146/2893 ... torba0.jpg
When complete table is copied in Excel, and we rearrange it a little, it looks like this. You can notice that all values are written 10X – 2D, 3D, overdrive, limits, UVD, thermal throttling? … Does anybody have it documented?
Now the question is: Which value to change? After thirty or more attempts best result is obtained by changing the 4th and 7th value in table, i.e. line 8th and 14th in Excel. By this way Overdrive limits are unchanged, and overdrive runs normal, 2D stays on default, and memory is not at its limit in 2D.
Here is the Catalyst CC def. look after BIOS mod:
http://img504.imageshack.us/img504/6024/catalystse6.jpg
I have used unchanged 2D at 300/892, for me, and changed 3D at 750/100 (def. is 669/829), and changed 3D GPU voltage from 1.214V to 1.327 V.
300MHz - 30 75 00
669MHz - 54 05 00
750MHz - F8 24 01
770MHz - C8 2C 01
1GHz - 10 27 00
1.05GHz - 04 29 00
1.1GHz - F8 2A 00
1.014V - F6 03 (2D for 3850)
1.214V - BE 04 (3D for 3850)
1.241V - D9 04 (2D for 3870)
1.327V - 2F 05 (3D for 3870)
Save it as ocbios.rom and copy it to USB bootable disk.
After booting, flash it to VGA using the command "atiflash -p 0 -f ocbios.rom"
7701000a.rom is with changed 2D voltage to 1.241V to improve OC.
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a to som len zdvihol a hned to islo takze som moc toho nenastavoval
