ATI 4850/4870 voltmod thread

[AliG]

so jimmyz how high did you get them cards?

[DemonEyez]

Hey you guys, here's a high res shot taken of my brandnew HD4850 if anyone needs it

Area for vGPU mod:


Area for vddr mod


I hope it contains all the area's you need


Didn't do the volt mod myself (yet), but 'm currenty running 700MHz core and 2300MHz ram.
That's with Enzotech ramsinks on the chips and a Swiftech MCW60 on the core (gives me 32 degrees celcius under 3d load)

[Jip]

it's the same pcb my sapphire

I'll follow the topic for pencil mod ^^

[gurusan]

Demoneyes, which brand 4850 do you have? Do you know which memory chips you have?

[Jip]

i mesure this :
Someone can told me where i must pencil for boost Vgpu ??

[K404]

Demoneyes: please can you take a DMM to the points marked (in blue) and tell me the resistance? (thanjks for the pics BTW!)



@ jip: any of the yellow points. Ideally the pin of the IC, if you can solder a point that small- maybe the yellow point closest to it would be easier

K

[DemonEyez]

Demoneyes: please can you take a DMM to the points marked (in blue) and tell me the resistance? (thanjks for the pics BTW!)



K

I'll measure this evening

Demoneyes, which brand 4850 do you have? Do you know which memory chips you have?

It's an Asus HD4850 ( EAH4850/HTDI/512 ) and it uses Qimonda chips:


This is how my card is cooled:

+


Gives me 33 degrees stessed, 700MHz on the core (could go higher, I reckon) and 2300 on the Qimonda chips

[gurusan]

nice. I have the HIS card and it uses the same Qimonda chips. My card was crashing at anything above 690mhz, so I forced the fan to 100% and turned 98c load into 57c...now it passes 700mhz no problem, so it was obviously heat related. I have a maze4 block on order to throw the card into my loop...I really hope we can get some ocing software soon as I think with a little voltage this thing could do well over 800mhz, hopefully more.

[DemonEyez]

Look what I found
:

HD 4870 uses 59PR9853 Multi-Phase SMD Coupled Inductor for GPU power supply, a really high quanlity one



You can see the VRM part take over almost half of the card

Source:
http://en.expreview.com/2008/06/23/a...6bit/#more-475

[gurusan]

Is there no way to Hex edit the bios as on the 29xx and 38xx series?

[alexio]

I guess this is the place to find people with multimeters (and big balls ). I made a 1.327v 3D BIOS for the HD4850, but I'm not sure if it will work, see: http://www.xtremesystems.org/forums/...d.php?t=192159
Please report back

[gurusan]

I have just done a pencil mod and it is confirmed working....it's 1.16 idle now and 1.24 load. will post a pic in a second

[DemonEyez]

So you're actually shading the pcb to create a new trace between the two solder points and not shading a resistor at all, right?

[gurusan]

Correct. there's no resistor there..just carefully making a trace between the 2 points

[DemonEyez]

Nice!
now if only CCC wasn't restricted to 700MHz...

[gurusan]

yeah. cant we hexedit the bios somehow

[JamesBong420]

anyone know what size pot to use for the vgddr mod?(4850) i havent read the resistance yet. but would be nice if i don't have to drive back and forth just for a $0.99 pot. thanks

[Errik89]

I have just done a pencil mod and it is confirmed working....it's 1.16 idle now and 1.24 load. will post a pic in a second

[IMG]http://img110.imageshack.us/img110/2151/4850core2lh9er5.jpg[IMG]

this pencil mod is easy to do? I've never do voltmod and I want to do pencil mod because the bios editor (like RBE) doesn't already work with RV770 (4850).

Can you tell me how I can do this pencil mod? Thanks!!

[DemonEyez]

Did some measuring and this is what I found on my Asus HD4850:

idle vgpu 1.05v full load vgpu 1.15v

idle vddr 2.01v full load vddr 2.01v

So it seems that my vgpu is somewhat lower on this card than on Jimmiz's who measured 1.20v for his vgpu

Demoneyes: please can you take a DMM to the points marked (in blue) and tell me the resistance? (thanjks for the pics BTW!)



K

Left pin I got 3.93Kohm

So 3.93K Ohms = 2.01V

[JamesBong420]

@demoneyes
thanks alot. just in the nick of time.. getting off work in 50 mins.. run down and grab me some VR's..

i see some people on hwbot have 1150+ mhz on the mem.. and i can only do 1085mhz.. so i shall see if a little voltage will help.. tide me over until we get more control over the core clocks..

all i know is the s1 is dieing for more volts i mean 37c fully loaded, beats the 81c loaded i had on the stock cooler.

[JamesBong420]

well just my luck.... imma have to order everything i will ever need for any future mods. my local radio shack no longer carries 100k trimmers(pots)..

so will a single turn micro trimmer work? as long as i turn it millimeters?

[Clemmaster]

What gain do you have with pencil mod? ~+0.05v?

I now realize how crapy the stock rad is, even with typhoon ON (never heard such a noise from a fan )

Edit :
@DemonEyez : mine is 1.06v IDLE / 1.153v Full (Powercolor)

[gurusan]

for me shading from 5.13 to 4.85ohms brought me from 1.06idle 1.16load to 1.16 idle 1.24load

[Clemmaster]

Ok Thanks

Any issues with temperature though?

[gurusan]

nope..only using the stock fan at the moment as well....controlling it with asus software. 30% fanspeed idle gives me about 48c....80% for gaming gives me about 58-60c. It will be underwater soon so then I'll be able to push it more.