ATI 4850/4870 voltmod thread

[gamervivek]

hello all,i am new here
i have a His IceQ4 card with me which is said to have a different pcb design-
http://img.hexus.net/v2/graphics_car...rdrear-big.jpg
any pencil mods for this card?right now i am at 730/1100 can bench at 740/1125 temperatures don't go beyond 58C in ati tool and 51C in crysis with 100% fan.

[gurusan]

Just finished another vGPU pencil mod. Using both methods I got the core up to 880 @1.42v. Anyone been using this high of voltage 24/7 for a while?

Its watercooled and uder 40c but I am still somewhat concerned I may be slowly damaging the card over 1.4v. I might back it down to 1.37v...but once you hit your maximum......

Set your idle voltage with RBE to .892 and it will measure around 1.08-1.1v idle. That way the GPU only sees full voltage when gaming.

[giorgioprimo]

Uh, yes. I understood that, and mentioned that the resistance from pin 19 to ground is ~9.58k. I'm only lacking tools and components. That and Jaycar doesn't appear to stock 200k trimpots. I still have to measure pin 6 to ground on the RT8105 though. Wouldn't mind having a rough idea of how much the voltage would increase when resistance goes from 9.58k to 9.15k (9.58k and 200k trimpot (set to max) in parallel).

did you have any success the vmod ?

can you edit the follow image to show were did you solder? and wich measure point you use to check the VGPU voltage?

[Brumi]

For people searching for the pencil mod point for the new sapphire card,I've found it.At stock it was 1612 ohms,giving 1.24V .Setting it to 1185 gave me 1.34v.Also the points used for measuring the voltage are different,see the picure(I will use one that other user posted so I don't need to take pictures myself).I'm yet to confirm the memory points,but I'm quite sure where they are,I will post it when I get the necessary cooling for my memories(the stock one doesn't even have a heatsink attached to them).I think this card has great potential for overvolting,with the stock cooler running at 100%,at 1.34v(with no overclock),I get 65°C (GPU temperature with GPUZ) after running Atitool "scan for artifacts" for 5 minutes,and overclocked to 795mhz it gets up to 70°C.



Edit:I was able to get up to 795mhz on the gpu,more than that and some tiny artifacts started appearing on Atitool.When overclocked the voltage goes up a little bit,at stock clock it's 1.335v and overclocked it get about to 1.347v.People with the same card,please let me know your results.

THNX man! In the afternoon i try to do it. After i post my results.

I mod your pic two + measure point:

[GamerBR]

THNX man! In the afternoon i try to do it. After i post my results.

I mod your pic two + measure point:

I didn't get what you added,did you think that because I marked it black it's the negative point?If so,that's not what I meant,I use the multimeter at those two points to measure the voltage.If that's not it,is it another way to measure it?Between those two new points you marked?

[GamerBR]

I've increased the vgpu voltage from 1.345v to 1.375v and I'm still unable to get more than 800mhz with no artifacts,I don't know if it's the limit of the card or it's my cooling that's bad(I'm using the stock cooler at 100% and with no cooling at the ram),I'm waiting for a new cooler to arrive,so I will find the answer soon.

[gurusan]

it could be cooling, also the VRMs get very, very hot. make sure you have something blowing over them

[Brumi]

Befor the mod: resistor: 1,612Kohm vgpu: 1,24V (idle) / 1,29V (load) Max stable clocks: 700/2100 Max bench clocks: 730/2200
After the mod: resistor: 1,402Kohm vgpu: 1,24V (idle) / 1,32V (load) Max stable clocks: 730/2100 Max bench clocks: 760/2200

I try to set lower the resistance and post results.

2 added measuring point is the same that yours, but i easy to measure when the card is in my case.

[Unrealer]

People with the same card,please let me know your results.

@ stock volts



RtHDRibl 1:30H
Crysis Warhead Benchmark 20 tests

830/4400 (im still testing...830/4600 is stable too)
fan @ 35% +-

[GamerBR]

@ stock volts



RtHDRibl 1:30H
Crysis Warhead Benchmark 20 tests

830/4400 (im still testing...830/4600 is stable too)
fan @ 35% +-

I meant for the non reference sapphire hd4850

Befor the mod: resistor: 1,612Kohm vgpu: 1,24V (idle) / 1,29V (load) Max stable clocks: 700/2100 Max bench clocks: 730/2200
After the mod: resistor: 1,402Kohm vgpu: 1,24V (idle) / 1,32V (load) Max stable clocks: 730/2100 Max bench clocks: 760/2200

I try to set lower the resistance and post results.

2 added measuring point is the same that yours, but i easy to measure when the card is in my case.

I couldn't get the resistor anything below 1481 K ohm using just pencil,you probably can do it trying with several different types,but I have some conductive glue here,I'm using it,I just pour a tiny amount over the resistor wait it to dry(a few minutes) and measure it,after several tries I was able to get the resistance that I wanted.

[GamerBR]

it could be cooling, also the VRMs get very, very hot. make sure you have something blowing over them

I was unable to find how VRM looks like,but I think it's the two gray blocks on the picure,right?Looking for the picture I've found the picture for the reference card too and it has 4 of it and they are smaller,I'm not sure if having less and bigger is better or not(probably not).

[NBF]

Double post

[NBF]

I would be happy with 1.4V.

My card has a very diferent layout from reference ones, I think Asus has 2 pcb models.

I'll upload some pictures ASAP, hopefully somebody can help me modding that.

Front


Back


Closer look


I hope it's good enough, if you need other pictures let me know

[Vatos_locos]

@ photo named Closer look what is written on the two chips ?

Ap-AG BD_AF and what else ?

[NBF]

@ photo named Closer look what is written on the two chips ?

Ap-AG BD_AF and what else ?

AP-AG V1F

BD-AF J1Z

[Vatos_locos]

crap i cant find anything for those :S

on the back the first chip on the upper ft side its next to BD-AF J1Z what is written on it ?

[NBF]

crap i cant find anything for those :S

on the back the first chip on the upper ft side its next to BD-AF J1Z what is written on it ?

Thanks for your help Vatos_locos

I hope its readable

[Mungri]

What is the default voltage on the 4870? I would really like to know and modify my 4850 to the same.

I have gone as far as 1.3v and couldnt even get my cards stable at 725 Mhz.

[gurusan]

I was unable to find how VRM looks like,but I think it's the two gray blocks on the picure,right?Looking for the picture I've found the picture for the reference card too and it has 4 of it and they are smaller,I'm not sure if having less and bigger is better or not(probably not).

No, they are the 8 black chips on the left, they need active cooling when clocking.

[GamerBR]

No, they are the 8 black chips on the left, they need active cooling when clocking.

It already has an heatsink,so all I need to do is add a fan to it..By the way what's the gray block then?

[largon]

The gray blocks are inductors - passive components, a bit like capacitors.

[GamerBR]

I decided to post where I think it's the point to use to increase the memory voltage also,I haven't tried myself but I'm quite sure it's there.Why?It's exactly the same resistor of the reference card,R710.That's how I guessed the point for increasing the gpu voltage(the indications on that case was harder to see,on the memory it was much easier),I just didn't do it because I have no cooling for the memories yet,if no one confirms it's there before me I will do it in about 1 week when my new cooler and ramsinks will arrive .Please,as it's not impossible that the point is wrong,measure the voltage before,change the resistance very slighly and see if there is an increase on the voltage,if there is,it's there

[Brumi]

Befor the mod: resistor: 1,612Kohm vgpu: 1,24V (idle) / 1,29V (load) Max stable clocks: 700/2100 Max bench clocks: 730/2200
After the mod: resistor: 1,402Kohm vgpu: 1,24V (idle) / 1,32V (load) Max stable clocks: 730/2100 Max bench clocks: 760/2200

I try to set lower the resistance and post results.

2 added measuring point is the same that yours, but i easy to measure when the card is in my case.

I could set the lower resistance, with a 2B pencil.

Resistor: 1,263Kohm vgpu: 1,29V (idle) 1,37V (load) Max bench clocks: 800/2250

I try the memory pencil mod in the afternoon. After i post my results.

My card cooling:

[GamerBR]

Are you getting any variation between stock clock and overclocked?If so,which one is the one you are posting?Nice setup there,what are the temps you're getting?

[ceemic]

I'm going to Vmod my HD4870. The point, where FB heads to isn't the best but doable. Tho I can't find any spot, where it also goes. There should be some resistor that connects FB to GND?
I measured huge amount of components front and back the card but no go...
http://ceemic.pri.ee/hardware/hd4870/hd4870_03.jpg
http://ceemic.pri.ee/hardware/hd4870/hd4870_09.jpg

And yes, FB->GND resistance is ~2,6ohm, so 50ohm VR works