ATI 3850/3870 Voltmod thread

[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.

[HousERaT]

I'm about to do the pencil mod for the 3870 memory. Anyone know how much Samsung says is the max for volts on GDDR4 memory?

[Blackoberst]

Thanks Norway!
The mod worked fine, benched 3DMark03 at 985/1250 stock cooling, fan spining at 100%.
The first mod is a bit hard to do, and didn't seem to work for me even though I shaded that resistor pretty good. The one you mentioned it's much easier.

[Norway]

HouseRat:

Don't know but I wouldn't go much higher then 2-2.1v, someone here tryed 2.3-2.4v and it didn't "boot"/no picture .....

Even 1.9v makes the ram go pretty hot !

BlackOberst: what are your voltage ?
The first pencilmod ?
A pic plz

[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.

[Random Murderer]

if you don't have a multimeter, how can you even be sure the lead stuck to the resistor?

[Riska]

You can se if the lead is stock on the resistor

[Random Murderer]

You can se if the lead is stock on the resistor

right, it may look stuck to the resistor, but you can't be sure that it's dropping the resistance at all if you don't test it.

[Blackoberst]

I didn't test the resistance with a multi, but if it had dropped I would've been able to clock the core higher. I know I'm not doing it by the book and I don't want to say that the mod doesn't work, but the one Norway sugested it's much easier. I think I didn't shade that resistor enough even though I tried for several times.

[Planet]

Guys how hot is your memory running under load. Mines in the 90C range right now

[Vatos_locos]

how do you measure it ? 90 *C is really hot and on what card 3850 or 3870 ? what Vddr ?

[Menhir]

right, it may look stuck to the resistor, but you can't be sure that it's dropping the resistance at all if you don't test it.

exactly....

i got a resistor drop of my resistor that i penciled from 2.44kohm down to 2.0kom to get 1.5V for my gpu

it dropped down to 1.46kohm and even cleaning using ethyl alcohol didnt worked

i used a needle to scratch the graphite from pcb between the resistors to get it to stock to pencil it clean down again

[-DC-]

hi guys. i'm just worried about the temperature of my 3870, it's about 100 degrees @ 918mhz core. Cooling is Zalman VF-900CU, and i thought it would be just ok for this card. Maybe there are some problems with my GPU? But even at 100+ degrees it's rock-stable in 3dmark 2006 AA8AF16 5runs...

second question.. i've stuck at 2400 with my samsung gddr-4, and it seems nothing can help me( Raising voltage only harms it as i see... 2.0-2.1 volts made it really hot and stable only @ 2300(((

[Clint]

Hello people, this is my first posting 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.

I'm thinking about buying the Gigabyte HD 3850 512MB version.
I know this is the image from the prototype, but maybe the memory is still the same on reatil?
What brand is it, from pic it looks like Qimonda?
I believe with those components the core will be very responsive to a voltmod.

[-DC-]

emmm.. is this thread dead?(((

[Vatos_locos]

-DC- 100*C is far away from good man my vga @ 1026 has 45*C under watter i think it's time to rma sorry

Clint just go for the 3870 IMHO 3850 with 512 is not a value for money

[purecain]

the heatpipes on your cooler might be faulty as those temps are unacceptible....

[-DC-]

hm, i have vf700cu also.. it's 10 degrees higher. But what's strange - the card is really stable in tests. And core can go up to 1000, but 100 degrees are really frightening Maybe there's a problem with some element's ground in the core?

[Vatos_locos]

or a faulty sensor but you have to rma your card

[-DC-]

not faulty sensor, cause the card is really pretty hot((

[Vatos_locos]

so the temps are correct then i'am afraid that you really have to ram your vga it doesn't mater that the card works at those temp it might just stop working today or in one year but it is not normal to run at 100*C

have you volt mod your card ? if yes how many voltage the core has ?

[-DC-]

now it's 1.43 volts