ATI 3850/3870 Voltmod thread

[Norway]

A voltmod (solder/pencil) would be a problem if you know how to find it ....

A BIOS change may be a little difficult, but if the BIOS dosen't have the 862Mhz limit then drop it and do a soldering vmod

All you need is to find the correct IC and find the FB pin, then solder a VR between and off you go :P

Value on the VR you need is the resistens between FB pin and ground x20 roughly calculated

FB = FeedBack

[Hola77]

A voltmod (solder/pencil) would be a problem if you know how to find it ....

A BIOS change may be a little difficult, but if the BIOS dosen't have the 862Mhz limit then drop it and do a soldering vmod

All you need is to find the correct IC and find the FB pin, then solder a VR between and off you go :P

Value on the VR you need is the resistens between FB pin and ground x20 roughly calculated

FB = FeedBack

Well I would kinda be more happy if someone could mod the voltages on my bios first.
I have very high hopes for this card, because the PCB is exactly the same as on the Gigabyte 3870 model. So I was hoping a bios mod could give me real 3870 voltages instead of the 1,28v all the other people with 3850 get.
By the way, my card is part of the "ultra durable 2" range. It has high quality components which reduce power consumption and heating. So this is another reason why I have high hopes for this card.

[MonsterMash]

Made pencil vmod, new vgpu is 1.512V .

This the results:

Freq. GPU: 1012mhz
Freq. RAM: 1301mhz x 2

3DMark06:



Crysis Bench @ 128x1024 all very high. DX10 on vista 64 bit:

================================================== ============
TimeDemo Play Started , (Total Frames: 2000, Recorded Time: 111.86s)
!TimeDemo Run 0 Finished.
Play Time: 110.36s, Average FPS: 18.12
Min FPS: 10.60 at frame 1942, Max FPS: 23.63 at frame 860
Average Tri/Sec: -12040729, Tri/Frame: -664394
Recorded/Played Tris ratio: -1.38
!TimeDemo Run 1 Finished.
Play Time: 103.22s, Average FPS: 19.38
Min FPS: 10.60 at frame 1942, Max FPS: 23.63 at frame 860
Average Tri/Sec: -12659318, Tri/Frame: -653346
Recorded/Played Tris ratio: -1.40
!TimeDemo Run 2 Finished.
Play Time: 102.75s, Average FPS: 19.47
Min FPS: 10.60 at frame 1942, Max FPS: 23.67 at frame 983
Average Tri/Sec: -12684731, Tri/Frame: -651668
Recorded/Played Tris ratio: -1.41
!TimeDemo Run 3 Finished.
Play Time: 102.24s, Average FPS: 19.56
Min FPS: 10.60 at frame 1942, Max FPS: 24.34 at frame 985
Average Tri/Sec: -12775948, Tri/Frame: -653119
Recorded/Played Tris ratio: -1.40
TimeDemo Play Ended, (4 Runs Performed)
================================================== ============

Max temp (@water cooling) is 40°C.
It seems to be RS.

[Blackoberst]

I have the PowerColor HD3870, not the PCS version and I've looked in this thread but it's a bit confusing. There are pics of HD3850/3870 and I don't know what is the exact pencil mod for my card.
I've atached a picture.



L.E. Which is the exact rezistor to shade?

[Norway]

...

[Sources]

Very nice. Im guessing with that mod and my Q6600 I should score about 14300.

Made pencil vmod, new vgpu is 1.512V .

This the results:

Freq. GPU: 1012mhz
Freq. RAM: 1301mhz x 2

3DMark06:



Crysis Bench @ 128x1024 all very high. DX10 on vista 64 bit:

================================================== ============
TimeDemo Play Started , (Total Frames: 2000, Recorded Time: 111.86s)
!TimeDemo Run 0 Finished.
Play Time: 110.36s, Average FPS: 18.12
Min FPS: 10.60 at frame 1942, Max FPS: 23.63 at frame 860
Average Tri/Sec: -12040729, Tri/Frame: -664394
Recorded/Played Tris ratio: -1.38
!TimeDemo Run 1 Finished.
Play Time: 103.22s, Average FPS: 19.38
Min FPS: 10.60 at frame 1942, Max FPS: 23.63 at frame 860
Average Tri/Sec: -12659318, Tri/Frame: -653346
Recorded/Played Tris ratio: -1.40
!TimeDemo Run 2 Finished.
Play Time: 102.75s, Average FPS: 19.47
Min FPS: 10.60 at frame 1942, Max FPS: 23.67 at frame 983
Average Tri/Sec: -12684731, Tri/Frame: -651668
Recorded/Played Tris ratio: -1.41
!TimeDemo Run 3 Finished.
Play Time: 102.24s, Average FPS: 19.56
Min FPS: 10.60 at frame 1942, Max FPS: 24.34 at frame 985
Average Tri/Sec: -12775948, Tri/Frame: -653119
Recorded/Played Tris ratio: -1.40
TimeDemo Play Ended, (4 Runs Performed)
================================================== ============

Max temp (@water cooling) is 40°C.
It seems to be RS.

[Norway]

Well I would kinda be more happy if someone could mod the voltages on my bios first.
I have very high hopes for this card, because the PCB is exactly the same as on the Gigabyte 3870 model. So I was hoping a bios mod could give me real 3870 voltages instead of the 1,28v all the other people with 3850 get.
By the way, my card is part of the "ultra durable 2" range. It has high quality components which reduce power consumption and heating. So this is another reason why I have high hopes for this card.

Well I think moding your BIOS is impossible atm, couse no one knowes how. (Have I misse something lately ?)
You can do a pencil mod if you don't want to solder it .....

[Blackoberst]

Norway, I was shading the resistor marked on the atached picture below. That is the mod I tried first but it didn't work for me.
I couldn't measure the voltage because I didn't have a multimeter, but I'm guessing 1.4xx volts for core because I couldn't bench at 1Ghz core.