ATI 3850/3870 Voltmod thread

[ryanmartini]

To keep from shorting the GPU voltmod you guys might also want to look at putting a fixed resistor in series with the VR... I would say a 10K fixed should do for most but it might be a bit high for getting 1.6v+...

Ok so with the VR soldered to the two points, where would the resistor fix into place?


Also, someone take some pics of the mod, dont be greedy!

[K404]

See my pics on the previous page.

The resistor would be in series with one leg of the pot.

ie: solder point-> resistor-> leg of pot

[Unoid]

Can someone share with us what Values of resistance equate to vgpu values?

I like toe hard wire w/o a POT. strait resistors ;-) But I'd like to use a smaller POT also. Everyone says 100kohm, but what do you end up at to achieve 1.5vgpu? 15k? 50k? if so I'll buy a 50kohm.
I haven't hard modded since my 9600Pro. Will be fun to volt and watercool again.

1kgpu on water and 1.5-1.6vgpu sounds like fun.

[JamesBong420]

3850 is here... give me a few days to mess with her then hardmod here we come!!!!!!!!!!! and chiller !!! ! !!

[winbond]

can someone post some real benchmarks of the overclocked 3870?

like crysis 1280x1024 with EVERYTHING maxed out, etc,

thanks

[Sage]

i can tell you that i run crysis at 1650x1080 with High Everything with a couple of settings Very High.

Though not really any use cause games arnt just dependent on ur gfx card. See my specs below.

[JamesBong420]

hardmod confirmed to work on the 3850. the stock 3850 volts are 1.22v 100k VR got it to 1.28 im at 1.3 816mhz core and still testing...

[slugzkea]

I believe my specs below are the most generic for today's setups and my comp should do the crysis bench.

All i need is a photographic diagram of the completed mod and I can get the mod done in less than 30 mins.

I know for sure that 1650x1050 crysis everything high at 877/2600 i get a good 20-30fps or lower.

[JamesBong420]

x2 3800 @ 3.0
Crucial Ballistix ddr500
msi 3850 823mhz/945mhz

9733 3d06- http://service.futuremark.com/compare?3dm06=4047261

im happy so far... 10k is my goal..

edit: 3d06 9889
850/999 1.44v http://service.futuremark.com/compare?3dm06=4047847

[R*r]

ive done the mod but i dont know why every time i set the core clock above 860 it will hang?ive set the vgpu at 1,5 1,4 doesent make any difference?

and if i set the core clock directly at 900 or above the core clock reading show me 34Mhz at riva tuner??very strange???

any one can help?

[the-strokes]

ive done the mod but i dont know why every time i set the core clock above 860 it will hang?ive set the vgpu at 1,5 1,4 doesent make any difference?

and if i set the core clock directly at 900 or above the core clock reading show me 34Mhz at riva tuner??very strange???

any one can help?

try the modified bios.

[R*r]

thanks man,now im benching @ 1G

[JamesBong420]

i wish the bios fixed the 3850s 860 mhz lock....

[os008]

Guys, what's a good up-to-date utility to edit an ATi BIOS file?

RadEdit, and RaBiT are way too old right now, will NiBiToR work, or is it only for nVidia BIOS'.

Thanks.

[Amrita]

thank's guys worked like a charm but i had to go 1,5 for a stable 945mhz
next step is to reseat my wb but i'm waiting til i'm adding a new card hafto rebuild my loop then anyway

any fix to get crosfire oc higer yet?

[SNiiPE_DoGG]

http://www.radioshack.com/product/in...entPage=family

what do you guys think of this potentiometer for the voltmod on the 3870?

[c.freak]

Has thee been any confirmed ideal voltage for the VDDR mod? and What VR-size/resistance should this POT have?
I haven't done hardmod since the 9800 and X800 time, so it's been a while
For the moment im only doing 900mhz on the core. Boring stockcooler soon goes off.

For the cooling later on i'll be using a triple-radiator + 6x 120 fans for my new MCW60's. Cpu,Nb+Sb will go off with the same cooling. For the moment not really finished with my project. So cooling shouldn't be any problem.

[largon]

http://www.radioshack.com/product/in...entPage=family

what do you guys think of this potentiometer for the voltmod on the 3870?

It would work but personally, I'd use a multiturn VR.
Single turn pots like that are very inaccurate for vmodding.

[SNiiPE_DoGG]

It would work but personally, I'd use a multiturn VR.
Single turn pots like that are very inaccurate for vmodding.

ty very much, im off to radio shack!

[JamesBong420]

finally broke 10k with my x2 3800 - 3850 850mhz/999mhz yahooooooo

http://service.futuremark.com/compare?3dm06=4075418

[MorGo7h]

finally broke 10k with my x2 3800 - 3850 850mhz/999mhz yahooooooo

http://service.futuremark.com/compare?3dm06=4075418

Gratz

[quake6]

finally broke 10k with my x2 3800 - 3850 850mhz/999mhz yahooooooo

http://service.futuremark.com/compare?3dm06=4075418

Now go for 11k

[MorGo7h]

Any differences between HD3870 and Vmodded? Since the Vmodded bioses dont work :/

Nvm: I saw some results on page 3 WTF! I want a 2nd watercooling loop!! :p

[R*r]

finally can touch 15k
http://service.futuremark.com/compare?3dm06=4087007

[SNiiPE_DoGG]

http://cgi.ebay.com/ws/eBayISAPI.dll...ksid=p3907.m29

i got one of these pots for my mod, opinions?