ATI 4850/4870 voltmod thread

[petrakov]

1.41V seems to be very early for OCP.
Is that card using the uP6201 to control vGPu?

NCP5388 thes its voltcontroler for GPU (powercolor HD4870)

[mAlkAv!An]

Ok, just had a look at the previous posts.
OCP can be nearly disabled by connecting Pin12 and Pin13 directly. I guess by simply adding a resistor the OCP limit can be raised step by step.

Can you pleasy check if that's the right one:

[petrakov]

i see PDF NCP5388
pin12 to pin13 directly = disible voltprotection

but I am not very suresure it will work

you think that will work?

[mAlkAv!An]

I think it will. In fact it's not really disabling but setting the OCP to a very high level which is nearly the same.

Instead of directly connecting both I would add a VR and tune it down to check if you can raise vGPU above those 1.41V.

Can you please check if that resistor I've marked is connected to Pin 12 & 13 and if so what's the reistance between both pins?

[petrakov]

pin12 to pin 13,R=15k ohm

see pic thes ist resistors conect to pin 12 and 13 and GND

[mAlkAv!An]

Ok I would just use the one I've already marked: http://www.xtremesystems.org/forums/...1&d=1282824804

You'll probably doing well with a 200k VR.

[petrakov]

how conect VR
VR to pin13 to GND?
VR to pin12 and pin13?

shem 1 or shem 2? how conect VR

[mAlkAv!An]

VR between Pin12 and Pin13. Just solder it in parallel to the marked resistor. Should be way easier than messing around with those little Pins at the IC

[petrakov]

tanks my frend from germany
im put VR paralel to pin12 and pin13 but not direc in IC
Im use anader soldier wet direct conet pin 12 and pi13

[mAlkAv!An]

im put VR paralel to pin12 and pin13 but not direc in IC

The effect is still the same.
You could also try to pencil that resistor but I guess that might not work.

[petrakov]

I do not like pencil mods,resistance is very unstable and here ist need precise value of resistance
I make thes manipulation wet VR resistor
Have you done this before(disable OCP)?
what video card with your?

[mAlkAv!An]

I've never had real OCP issues with any card, even though I've tested 'a few'.
Nevertheless I did some searches and that's the way how to change/disable OCP on NCP5388. So let's see how it works for you

[petrakov]

operation is ready and work
now pin 12 connect direct wet pin 13 (disable OVP) and Ugpu=1.430v
1.430V=860Mhz max
1.450V=860Mhz max
1.480V=865Mhz max
im testing videocard but max frequency ist 860Mhz (free artefact)
card work 860/4800 thes ist max frequency overclock (bad luck)

thanks for help

[mAlkAv!An]

That bites... at least the OCP mod seems to be working.

[petrakov]

im make new test
artifacts are of RAM memory-(wery hot 89C)
run test 870/4400 (Ugpu=1.430V) and no artefact
i make more test wet difrent frequency memory and will localize max stable GPU frequency/RAM frequency,my goal is 900mhz GPU

[mAlkAv!An]

Good to hear it keeps scaling. Go for that 900MHz

[Avidgamer]

Hey guys,

I've had a gainward HD4850 for quite a while now, and it's showing its age, so I thought about volt modding it. My soldering skills leave much to be desired so I would have to try a pencil mod. The only issue is the board is non stock, identical to this one in fact:
http://ceemic.pri.ee/hardware/hd4850gs/ (shown on page 43).

If anyone can assist me in identifying the correct resistor to pencil, it would be much appreciated. If needs be, I can take my card out for some pictures but I cannot remove the heat sink as I have no thermal paste at the moment.

[ziggo0]

Just wanted to report in before I retire my 4850's. They are reference models, been at nearly 1.55vGPU each for the past year (under water, of course). Temps stay at low to mid 40's, 950/1200 bench stable but certain games are picky with the memory, then picky with the core. I found that overall 900/1150 to be stable.

[Rasmus66]

Is there any mods out for the XFX HD4870 with the egg cooler?

Think the print is there own design.

Here is a picture of the voltage chip.

[D0m|nat0R]

measure the resistance between point and GND after that you adopt trimmer 20x bigger than him

Wait for some confirmation of this

http://i220.photobucket.com/albums/d...k/IMG_6812.jpg

[Rasmus66]

measure the resistance between point and GND after that you adopt trimmer 20x bigger than him

Wait for some confirmation of this

http://i220.photobucket.com/albums/d...k/IMG_6812.jpg

Thanks that was the right spot mod works fine.

[Wumpus]

just volt modded my sapphire non-ref 4870...vcore mod worked great!

Went on to solder read wires and something was wrong. I soldered the wire to the output side of a choke, booted up with probe measuring and got the 1.33v that it gives stock...but mobo stopped on 2b error! I quickly took off mod and read wire but now it is continuing to do the same thing! Like somehow attaching a wire that wasnt connected to anything killed it!

if anyone knows what may be up that would be amazing!

[vega05]

Hi guys.
I apologize for my English is bad, but I'm Italian;-)
I wanted to ask if anyone knows where I can find and read points vgpu vmem HD 4870 1024 MB Club 3D the pcb looks identical to that of the PowerColor welding points are the same even with the meter readings are the same, I ask also that resistance should I use vgpu for 50k right? vmem resistances used for that? , OCP is required to go to 1.40v lotr?
if someone did it and I do explain where I would be grateful!
I've got a pot gpu that can not wait!
Thanks guys.

[Wumpus]

If PCB and IC are the same, vmod is also the same.

[vega05]

Thanks for the reply.

it is the same as the Vmod just do not know where are the points of reading and vgpu vmem, someone can 'tell me?

thanks guys