ATI 4850/4870 voltmod thread

[Factotum]

Factotum, 47k ohm is what? Resistance between FB and GND?

R4000=47kOm

[ceemic]

Why did You measure that resistor? Is that connecting FB to GND?
You need to know resistance between FB and GND.

[Factotum]

thx.
from datasheet:

FB and GND - where?

[ceemic]

You have to find some bigger GND point near that IC. You found FB allready, so just measure resistance between FB and GND. Remove card from PC before that ofc!

[Factotum]

done

[ceemic]

Always double-check all measurements. For example between directly pin4 and pin18.
If 1,1k ohm is right, then 20k ohm VR works fine.

[Factotum]

double-check and done
Asus EAH4870 1GB non-reference PCB:

thanks to all

[Factotum]

bad vcard =((

Vgpu=1.3V:


Vgpu=1.35V

[Ruma]

bad vcard =((

Vgpu=1.3V:


Vgpu=1.35V

Try 1.4v Just watch the temps, but 880mhz it's not bad

[OverShocked]

double-check and done
Asus EAH4870 1GB non-reference PCB:

thanks to all

Thought the eah4870 used reference pcb? Or is that just the 512 mb version?

At any rate, anyone know at what point will i usually need OCP for a 4870?

Also, is there any places that added caps would be helpful for a 4870?

Thanks

[CL3P20]

@ overshocked- I have benched 1.6v without OCP..on 4870 mod... as well, the GPU did much better with more 16v input caps. I added 6.3v output caps, with little to no gain.

[OverShocked]

Thanks cl3p20,
So what like 1000uf caps?

So any of these will do?
http://www.mouser.com/Passive-Compon...FR6Z2AodAXR8Jg

Thanks.

[CL3P20]

Yes those will work just fine. I like Nichicon.. but they are expensive.. Chemi-con work good too and better prices.

[OverShocked]

kk thanks m8,

PMed on OCN.

[FragZero]

So i got a cheap 4850 to replace my dying 8800GTS 320mb.

4850 512mb reference design
accelero S1
Vrm-heatsink sawed of the stock heatsink
Medium-speed 120mm fan blowing on vrm heatsink

But seems i got a crap overclocker...

Stock 675/1025 stable

1.3v 735-740
1.35v 760-780
1.4v 800-810

Currently running 800/1000 1.39-1.4v

Am i doing anything wrong? Only using Vgpu mod since ram mod has killed cards. Using the stock bios.

Max temps after 2 hours of Battlefield Bad company (roomtemp 23-24°c , summer!)

Core 52°
DISPIO 52.5°
MEMIO 65.0°
SHADERCORE 57°

Seems okay, certainly with hot ambient temps. I have decent caseflow and the 120mm is blowing on the ram, it's fine without ramheatsink.

But i was wondering, has anyone been running his 4850 on 1.4v for 1year+ ? It's only a 60euro card but it'd still be silly to blow it up!

Playing Bad company at 1280x1024 All high 2xAA and smooooth gameplay! Too bad i have a P35 16/4x motherboard or i'd get a second one for crossfire

[Aragarn]

HI any1 can help me with a pencil mod
for my 4850 Video card ? Is a his 4850
and has a non reference pcb ,
can any1 point me
where is the resistor
i need to shade?
His 4850 Fan Edition....
Also His has a 4830 fan edition same
Pcb maybe some1 know how to do a pencil on that !!

[CL3P20]

[Aragarn]

Thanks Cl3p20 but that picture is for stock PCB that use up6201bq-vlp824 my video card use a up6201bq-vlp896 and the resistor i need to shade is not in same place like on the stock PCB cards, any ideas how can i find the spot where i need to shade ?

[CL3P20]

Its still the R685 resistor.

[Aragarn]

Its still the R685 resistor.

So the resistor i need to shade is R685 ? on other pictures i saw is r1687 like in this picture :http://yfrog.com/gi4850shphj the bord was a 4850 sapphire
and also same card a person told him to do like in this picture http://yfrog.com/5bvmodareawm9j
but the guy shade the r1687 resistor and it worked like in the 1st picture ! Also for the stock PCb the read of scheme is not like in this picture ??http://yfrog.com/jv4850stockj
Maybe im wrong but if im not the r1687 resistor is shade !! Thanks for your Help

[CL3P20]

Hmm..do you have a DMM to see if the resistors are connected, I cannot make out the paths visually from the pics, and have sold my 4850's. The R685 is just adjacent to the location the other users mod'd from..they could be connected..

[Sennebring]

I´ve searched for days after an hardmod for ASUS 4850 TOP mem mod.
Got the GPU mod finished but I want to mod the memory too
Hope some one knows!

[NBF]

I´ve searched for days after an hardmod for ASUS 4850 TOP mem mod.
Got the GPU mod finished but I want to mod the memory too
Hope some one knows!

Im not sure if all 4850 TOP have the same pcb. If yours have same I had, then all you need to adjust Vmem is a 100kOhm VR between the blue marks.

[Sennebring]

Im not sure if all 4850 TOP have the same pcb. If yours have same I had, then all you need to adjust Vmem is a 100kOhm VR between the blue marks.

Thanks man! Your my hero of the day
I think Asus got one reference pcb and one for the top models which we got

[Mielemann88-DOS]

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