ATI 3850/3870 Voltmod thread

[the-strokes]

@ jimmyz / norway ; what's the resistance value (Ω) on the Vr to get 1.5v / above on VGPU ?

[eva2000]

Is this what you wanted? here is one of my modded cards, with v-core read point and a removable jumper for when I'm not benching.

http://img215.imageshack.us/img215/1...tmod026pi4.jpg

thanks but it seems my card backside is slightly different seems like a few more resistors exist on my than the reference ones - see http://i4memory.com/reviewimages/vid...IceQ3_007.html ?

[Riska]

Mine Sapphire 3870 can do 1331mhz on mem without vmod and stock voltage is 1.911v but when i do the vmod and set it to like 2.20v i cant go higher wy? how high voltage do you need for them mem on the 3870?

[Vatos_locos]

2,3Volt for every day should be fine but not more....
i don't know why you can't go higher but i thing that the memory frequency on those cards is already maxed out but i haven't try the mod yet so i can't really tel you why

[Norway]

Vatos locos:
You talk about GDDR3 me and Riska talk about GDDR4 and 2.3v is ALOT (!!!) for GDDR4 .....

I wouldn't go any higher then 2.1v for everyday use under good cooling ....

I didn't do any thing special to hit 1400Mhz and that was on 1.95v, take of the mem HS and take a pic of one mem modul or just write down what is writen on it, also interesting to know what brand your card is Riska, mine is
Sapphire

Edit: i have done the OCP mod on both of my cards and they still lives
The resistors to replace is very small, i used size 0805 and they was a little to big so 0605 should fit just fine

[Menhir]

Vatos locos:
You talk about GDDR3 me and Riska talk about GDDR4 and 2.3v is ALOT (!!!) for GDDR4 .....

I wouldn't go any higher then 2.1v for everyday use under good cooling ....

I didn't do any thing special to hit 1400Mhz and that was on 1.95v, take of the mem HS and take a pic of one mem modul or just write down what is writen on it, also interesting to know what brand your card is Riska, mine is
Sapphire

is your card a 3870 with GDR4 memory or a 3850?

what voltage do u suggest for my 3850 512MB with Samsung 1.0ns ram

i've a vmod vor the GPU with 1.41Volt and can get GPU clock of 864Mhz
my ram is currently not vmodded and runs at 1035Mhz

my cooling is an accelero S1 with two 92x92 fans @ 12volt but without ram heatsinks because the ac heatsinks are crap

is it enough cooling when the fans blow direct onto the GDR?

[Norway]

You can pump up the volt, but wouldn't recommend you to nor run them without cooling 24/7 with more voltage.

On my 8800GTX (1ns memory) I used 2.24v to get 1215Mhz on the ram but I used swiftech ram sinks

I don't recommend swiftech becuase they always fall off

[Menhir]

You can pump up the volt, but wouldn't recommend you to nor run them without cooling 24/7 with more voltage.

On my 8800GTX (1ns memory) I used 2.24v to get 1215Mhz on the ram but I used swiftech ram sinks

i was wondering because on my gecube 3850 turbo III the stock cooler doesent overlap one of the ram chips...

I don't recommend swiftech becuase they always fall off

that was my problem with this ac S1 heat sinks

[Riska]

When i set it to 2.31volt the thing articfats alot and crashes instant?

[Riska]

Ok thanks norway i couldent understand wy it should be that high...

[Vatos_locos]

oh my bad i read 3850 sorry the yhea 2.0Volt are fine for 24/7 more for benchmarks only

[Riska]

Here is a good closeup of the vmem chip area.

[Riska]

Is there anyone ho has gained any Mhz on the Mem with Vmemmod??
No matter what voltage i set it to i cant get it any higher than with stock voltage!
Is there some other mod i have to do like in the old ati 9700-9800pro days there was 2 mods for the mem...

[Cha0s]

Hm doesnt it give a pencil-Vdimm mod?
Bios + Pencil Vgpumod is done and it rocks ^^
but now i wanna raise the Vmem...

[Riska]

http://www.xtremesystems.org/forums/...d.php?t=171996

Here it is

[Riska]

Here marked in green

[Zannema]

Thank Riska

[Cha0s]

So i did this pencil mod on R1222 for increasing vGPU ..
but more than 840Mhz will result in a hang in CSS

so i will try this hardware mod tomorrow.. if I could reach 1ghz GPU ,..it would be cool

my cooling is : Accelero S1 + 2x 92mm Cooler


should be enought cooling or not?

[Menhir]

So i did this pencil mod on R1222 for increasing vGPU ..
but more than 840Mhz will result in a hang in CSS

so i will try this hardware mod tomorrow.. if I could reach 1ghz GPU ,..it would be cool

my cooling is : Accelero S1 + 2x 92mm Cooler


should be enought cooling or not?

what card and voltage do u have?

i've a 3850 512MB and use same AC S1 + Dual 92x92 Fans@12Volt
my gpu clock is 905Mhz and voltage 1.47volt
temp is max 60°C load

i think the cooling should be enough but i bet i will not reach 1Ghz gpu clock even with more than 1.5Volt

[Cha0s]

what card and voltage do u have?

i've a 3850 512MB and use same AC S1 + Dual 92x92 Fans@12Volt
my gpu clock is 905Mhz and voltage 1.47volt
temp is max 60°C load

i think the cooling should be enough but i bet i will not reach 1Ghz gpu clock even with more than 1.5Volt

Voltage now is about 1,38 with the pencil mod @HD3850 at 840Mhz core...
and thats not enought for me
ok 1000Mhz is not a "must have" but 900 should be reachable or not?
With 1,5v it should be,...?

and how did u mod it? with a variable resistor or even with the pencil mod`?

[Menhir]

Voltage now is about 1,38 with the pencil mod @HD3850 at 840Mhz core...
and thats not enought for me
ok 1000Mhz is not a "must have" but 900 should be reachable or not?
With 1,5v it should be,...?

and how did u mod it? with a variable resistor or even with the pencil mod`?

its never enough until the GPU is dead
the 900 should be possible for you

i modded it using pencil mod and fixed the mod using sticky tape that pencil is not blown away

[Cha0s]

its never enough until the GPU is dead
the 900 should be possible for you

i modded it using pencil mod and fixed the mod using sticky tape that pencil is not blown away

hmm nice ,.. ok i try one more time to pencil it ...
if 1,5V are possible just with this

now i get about 40°C @ idle...


EDIT:
BANG after i penciled it one more time i could get 940 core speed benchstable everything i wanted
and the temperatures are really cool with 42°C directly after the Bench 3D Mark 06

Now i got 12099 Points

[gurusan]

I can go all the way to 953mhz stable @ 1.5v, but to get to 1012mhz I require 1.6v!! I only crank it up that high for benching :p

These new ATI cards seem to love the volts, even the 3870s

[Vatos_locos]

mine 3850 with 1,65 Vgpu can benche A 1026Mhz Core :p and with 2,25Vdimm @ 2200Mhz Mem i don't know why my mems are so low

http://www.hwbot.org/result.do?resultId=686058

[JamesBong420]

anybody replace the caps on there cards?

my card used to do 1004mhz core and now that i have the chiller on it. it wont even stay constant 972mhz even. i get the dreaded checkerboard artifacts.