ATI 3850/3870 Voltmod thread

[purecain]

i just used the pencil mod on the r1222 resistor marked blue on both my 3870's and have no improvement at all.... i used a hb pencil and completely covered the top of the resistor... anyone got any ideas... should i take them out and pencil mod the resistor marked in black???????
any advice appreciated....

[BATISTA]

hi i have the 3870 club3d when i use other bios the performance is bad in 3dmark, and when i use the orginal than i can go only core 850 mhz ,
can i or can someone modify my bios 4 unlock it ??

i try all the mod bios all the same i can only use the orginal bios 4 good performance

3dmar03 72K@CF 850Mhz Core, and when i use other modbios@1000 Mhz core i get onky 53K with CF

i need unlocked Orginal bios and also need more mhz above 900 Mhz core
i do the Vmod but i cant go above 850 Mhz core
best regard


Withe Original and Unlocked bios i get this score

[purecain]

cant be done... original bios has a differant hex file... you must use the unlocked version.... i have a thread about it here http://www.xtremesystems.org/forums/...d.php?t=168407
theres a link to the best performing bios around..... have fun....

[Rumon]

i just used the pencil mod on the r1222 resistor marked blue on both my 3870's and have no improvement at all.... i used a hb pencil and completely covered the top of the resistor... anyone got any ideas... should i take them out and pencil mod the resistor marked in black???????
any advice appreciated....

Best way to is to use a Multimeter to measure the resistance after you have done the pencil mod.

First time i tried the pencil mod it simply didn't work and the resistance was the same. you will need to get the resistance down to at least 1/1.10KOhms to notice an improvement.

[purecain]

by re-applying i assume.... am i right? and have i used the pencil mod on the correct transister.. the blue one from the pic... thankyou for you expertise in this matter... i actually dont own a multimeter... i'm ordering one online as we speak.. which is the best to buy... is there a make of multimeter which is known as being the best or will any do... thankyou...
i would appreciate advice on which to buy from this site... money is no consideration... http://www.ni.com/digitalmultimeters...ity=multimeter

[Rumon]

Yes your right if it didn't work i reapplied and tried again and the blue one marked on the picture dose seem to be the one that works on the 3870 also.
As for a DMM. I don't know any brand or what is the best as i am just using a bog standard one i bought for back in my electronics course in collage
still works great its something like this.

DMM
(my current ones something along the line of that $20 one)

Also i had a hard time using a HB pencil try something along the line of 2b/3b/4b

[BATISTA]

cant be done... original bios has a differant hex file... you must use the unlocked version.... i have a thread about it here http://www.xtremesystems.org/forums/...d.php?t=168407
theres a link to the best performing bios around..... have fun....

hi i try already the bios from the site but no good 4 my club3 i think that the timings alre not good maybe

[purecain]

thanks for that m8 .... got one on order... i'll redo the pencil mod aswell...

[Rick Hunter]

Here's my pencil mod results on my HIS 3850 512 MB IceQ3 Turbo.

__ohm Volt MaxMHz Temp
2.26K 1.31V 826 MHz 48
1.38K 1.36V 850 MHz 51
1.45K 1.39V 876 MHz 53
1.13K 1.44V 904 MHz 56

Penciling in 1.13Kohm was not easy.

Scales pretty linearly across the board. Stable in 3DMark06 and AtiTool artifact tester.

I also slapped on a different fan onto the original heatsink, an 80 CFM Delta 80mm @ 70%. Brought down the temps by about 7 degrees on average.

Update:

After a day, the pencil mod wore off a little bit. I redid the pencil mod with the aforementioned technique (over the top of the resistor). Here are the new results:

__ohm Volt MaxMHz Temp
1.13K 1.44V 904 MHz 56
1.19K 1.43V 891 MHz 56
0.99K 1.46V 918 MHz 56
0.99K 1.46V 918 MHz 49 (delta @ 100%)

Ambient temp is about 23-24 degrees.

[KainXS]

This i guess

is that really for the 3850, I tried shading that on my 3850 256MB and its not working, anybody got an idea

[Wallboy]

Update:

After a day, the pencil mod wore off a little bit. I redid the pencil mod with the aforementioned technique (over the top of the resistor). Here are the new results:

__ohm Volt MaxMHz Temp
1.13K 1.44V 904 MHz 56
1.19K 1.43V 891 MHz 56
0.99K 1.46V 918 MHz 56
0.99K 1.46V 918 MHz 49 (delta @ 100%)

Ambient temp is about 23-24 degrees.

Wore off? So when applying this mod, one has to redo it quite often or what?

[Rick Hunter]

Wore off? So when applying this mod, one has to redo it quite often or what?

Not if done properly heh. I was initially using a thin-tipped cartridge pencil and was going around the resistor many times. Later, I found a regular 2H pencil, wiped the previous application and went over the top of the resistor. I remeasured it today and the resistance was the same.

[Bo_Fox]

Not if done properly heh. I was initially using a thin-tipped cartridge pencil and was going around the resistor many times. Later, I found a regular 2H pencil, wiped the previous application and went over the top of the resistor. I remeasured it today and the resistance was the same.

Well, then how long would this 2H pencil mod last? LOL... How do you measure the voltages if the measuring points are so far inside of your case? My case is so full of hard drives and cables that completely block any access for me to that area! Any ideas or suggestions for me?

[BATISTA]

do someone vmem on hd3870 ?? howmuch vmem can i give ??

[Rick Hunter]

Well, then how long would this 2H pencil mod last? LOL... How do you measure the voltages if the measuring points are so far inside of your case? My case is so full of hard drives and cables that completely block any access for me to that area! Any ideas or suggestions for me?

It should last longer than a day if done properly that's for sure. I've got just enough room in my case for the multimeter probes to touch the vGPU measuring points. It's not that easy and one really needs a steady hand while measuring the vGPU. You could always simply measure the resistance each time you try to do the pencil mod and compare that to what my results (or anyone else's) are. Granted, it's less accurate but might be a better alternative than blindly sticking two metal probes onto a running video card. :P I wouldn't go below 1.0 kohm (which usually increases vGPU by about 0.10V to 0.14V) unless you've got modded cooling.

[demolitionman1]

Hey guys,

here is a pencil MOD for the HD3870/3850 you can check. On my Club3D HD3850 this is 100% functional. The best is, there is no resistor so it is easy to clean. With 4,38-4,40 Ohm I got 1,4 - 1,41 VCore.

http://www.computerbase.de/forum/sho...d.php?t=357301

Its in German, but I think pictures says more than words

Demo

[Greg_1]

I can't get my GeCube 3850 512mb X-Turbo III over 850MHz on gpu it has 1.46V at 850MHz everything is just fine little bit over crash, is it bios limitation ?

[toddm27]

quick question, in the first post for the vcore mod it has 2 pot values, what vcore roughly does the 100k ohm put to the vgpu at max value?

[STaRGaZeR]

Hey guys,

here is a pencil MOD for the HD3870/3850 you can check. On my Club3D HD3850 this is 100% functional. The best is, there is no resistor so it is easy to clean. With 4,38-4,40 Ohm I got 1,4 - 1,41 VCore.

http://www.computerbase.de/forum/sho...d.php?t=357301

Its in German, but I think pictures says more than words

Demo

Thanks! Can you at least translate the pictures? Seriously, I don't understand a single german word

I´ll test it in a few days

[Rol-Co]

think this hardmod is working great

[toddm27]

nice, what volts and cooling? and did you do the mem mod too or just the gpu?

[GenTarkin]

would appreciate someone explaining those pictures just posted of the new pencil mod. I assume to connect the yellow points with pencil for the 3850...but what is with the blue points? one being the screw...

[Rol-Co]

nice, what volts and cooling? and did you do the mem mod too or just the gpu?

vgpu 1.52v
cooling: innovatek 7800gtx waterblock's (have 2 cards)

only the vgpu, it look's like vmem has a advantage on that too....i could never reach 1400 until now.

[mascaras]

Thanks! Can you at least translate the pictures? Seriously, I don't understand a single german word

I´ll test it in a few days

i think :


yellow >> pencil

Blue/Red >> measuring points

I can't get my GeCube 3850 512mb X-Turbo III over 850MHz on gpu it has 1.46V at 850MHz everything is just fine little bit over crash, is it bios limitation ?

do you have the HD3850 bios Fixed or original bios ???


regards

[demolitionman1]

i think :


yellow >> pencil

Blue/Red >> measuring points





do you have the HD3850 bios Fixed or original bios ???


regards

So it is! Yellow is pencil. Blue is measuring point for OHM. Red is measuring point for Voltage.