ATI 4850/4870 voltmod thread

[GeForsik]

Does anyone know how to make Vmods on Asus 4870 Glaciator PCB? This PCB got 4+2 phase.

+1, i need it too

[Rick Hunter]

After deciding that my 3850 @ 900 (pencil vmodded to 1.44V) wouldn't be fast enough to run Mechwarrior Living Legends (Crysis mod), I picked up a used Gigabyte 4850 512MB with the Zalman cooler (GV-R485ZL-512H). Plopped it in a test rig and began OCing from the stock 625/993 speeds. Only upped the gpu voltage to 1.158 (max I could set it to via ATT - the Gigabyte Gamer HUD reports 1.24V which is not correct) and ended up with this seemingly stable result after a couple hours of testing in 3dmark and furmark:

825/1200 !!

It hard locked at 850/1200 in '03 within the first few seconds of GT4 Nature. Haven't tried any speeds between 825 & 850.

No vmods.... yet - will look into them when I have more time.
What a gem!

[edit] - darn, no pencil vmods yet. I'm considering the hardmod posted earlier (FB pin 17) but have a bit of an unsteady hand when it comes to soldering small parts :/ Any tips for an old-timer?

[bronco113]

Hi,

this is my HIS 4850 IceQ TurboX - 512Mb:




I think it's non a reference one, so... I'l like to do just a simple pencil mod for the VGPU,
can you help me, please?

It seems that it's not possibile to do the "first" pencil-VMOD, because there is no resistor there.

The second one, for more that 1,4V for VGPU, is possible, according to you or not?

[bronco113]

Hi,

this is my HIS 4850 IceQ TurboX - 512Mb:




I think it's non a reference one, so... I'l like to do just a simple pencil mod for the VGPU,
can you help me, please?

It seems that it's not possibile to do the "first" pencil-VMOD, because there is no resistor there.

The second one, for more that 1,4V for VGPU, is possible, according to you or not?

Really no one for me?!

[nullface]

This might be a long shot, but are there any BIOS voltage mods for a Gigabyte custom PCB 4850 (GV-R485ZL-512H), it has the "GamerHUD" chip and can adjust voltage in the GamerHUD but not by much.

[flips]

I'm searching for the Pencil Voltmod for the Powercolor 4830 too...
can anybody show on the pictures where i have to draw the resistors?

hi,

thx for reply - here they are












http://www.abload.de/image.php?img=img_2341tw4b.jpg
http://www.abload.de/image.php?img=img_2338rnx6.jpg
http://www.abload.de/image.php?img=img_2339h8da.jpg
http://www.abload.de/image.php?img=img_2336t8u9.jpg

[arroyo]

I want to make v-mod on the reference HD4850 simplest way possible. I do not trust my soldering skills

and I do not like pencil mods, because they change their properties after some time. However, I ran an idea:

What do you think about this:
1. I change BIOS voltage values using RBE 4 units down (instead of 1.158V will be 1.006V, etc.)
2. I would flash the card with the modified bios.
3. I would paint a resistor with conductive paint using method similar to pencil mod (method for below 1.4V)
4. I would OC and change the voltage in bios.

What I should get
Since the pencil mod on the resistor provides a maximum of 1.4V under stress, I will reduce this value in the BIOS to

1.24V. I could peacefully (without the use of potentiometer) flash card to voltage that I like (maximum of 4 units higher,

So 1.28V, 1.32V, 1.36V and 1.4V). Resistance will not change after a month, because mod will be executed by paint instead

of graphite pencil.

What am I afraid:
- That the short-circuit resistor hurt anything.
- That a maximum of 1.4V at the method of the resistor is fake, and indeed it is a much higher voltage
- That despite the settings in the BIOS, the card will receive the maximum voltage (> 1.4V)
- That no one never tested it and it is madness.

Can anyone allay my fears before I burn my HD4850

[Sno0p82]

hello,

someone can help me with my non-ref 4870? voltage phase base on NCP5388 chip. http://datasheetz.com/ONSEMI/NCP5388-D/NCP5388-D.html << there is data sheet. pin vfb is correct?

thanks for help
snoop

[CL3P20]

hello,

someone can help me with my non-ref 4870? voltage phase base on NCP5388 chip. http://datasheetz.com/ONSEMI/NCP5388-D/NCP5388-D.html << there is data sheet. pin vfb is correct?

thanks for help
snoop

FB = pin 19... measure resistance from pin 19 to ground and * 20 for VR size needed to hardmod... you can use continuity on your DMM to trace pin19 to a resistor or pad to make mod a bit easier...landing to IC's can stink sometimes.

[Sno0p82]

FB = pin 19... measure resistance from pin 19 to ground and * 20 for VR size needed to hardmod...

ye i think that too.

20k vr?

now i must find vgpu measure point.

thx

[CL3P20]

Mmm..not a 20k VR unless you have verified. You need to measure the stock resistance value of pin19->grnd... then

[stock R * 20 = ~VR size needed for mod]

so if stock resistance is 2.07k..2.07*20 = 40.14k ohms.. so you would have to either put 2x 20k ohms in series or use a 50k for the mod.


**GPUv = measure from the back of either one of the two large grey 'cubes' adjacent to each other...those are the inductors for GPUv phases... the 1x off near the edge of the PCB is the inductor for vMEM if your curious where to measure mem voltage from as well

[marcooxx]

Hi all I 'm new for this nice site

I have sapphire 4870 1gb vaporx and i know the voltmod software is not possible .
I don't have the volterra chips in
I want overvoltage it with hardware mod (no problem with soldering) but my pcb is blu and anymore photo for the mod are present in intenet
my photo:

http://img138.imageshack.us/i/okr.jpg/

http://img715.imageshack.us/i/ok1r.jpg/

[ceemic]

marcooxx, first - please use thumbnails or links for these huge pics!

Locate pin 10 on that IC and trace it. The angle of the photo was bad so I'm not quite sure, but pin 10 might be there: http://ceemic.pri.ee/hardware/all/hd4870_up6207.jpg
Then measure its resistance between GND. Card removed from PC first ofc!

[marcooxx]

marcooxx, first - please use thumbnails or links for these huge pics!

Locate pin 10 on that IC and trace it. The angle of the photo was bad so I'm not quite sure, but pin 10 might be there: http://ceemic.pri.ee/hardware/all/hd4870_up6207.jpg
Then measure its resistance between GND. Card removed from PC first ofc!

Yes the pin is that and the resistance is 6,98kohm .
I must put a trimmer there ??

Thz !

[ceemic]

Always double-check all measurements. For safe use, 200k ohm VR is fine. Or You can use 100k VR + 50k VR in series.
You have to put the VR between FB and GND yes. You can use one of the two points I marked for soldering. For GND use some bigger SMD cap tip nead IC.

[marcooxx]

Always double-check all measurements. For safe use, 200k ohm VR is fine. Or You can use 100k VR + 50k VR in series.
You have to put the VR between FB and GND yes. You can use one of the two points I marked for soldering. For GND use some bigger SMD cap tip nead IC.

Ok but where misure the voltage variations of gpu voltage ?

Sorry for my English

[ceemic]

Possible Vgpu measure points: http://ceemic.pri.ee/hardware/all/hd4870_measure.jpg or coil-legs below.

[marcooxx]

Possible Vgpu measure points: http://ceemic.pri.ee/hardware/all/hd4870_measure.jpg or coil-legs below.

Good ,,Thancks
Now i try to mesure the voltage in that points for vcore then the rest

[marcooxx]

Oh yess in that points are 1,26v

For the bios i must change and the vmem is possible do anything ?

[ceemic]

marcooxx, what do You mean? For Vmem You have to hard-mod also.

[petrakov]

hi,all

how to voldmoding my powercolor hd4870 PCS+ ,512mb ddr5,256bit ?
now im overclocing thes videocard wet rivatuner (840/4400)
will be overclock GPU ..900mhz wet voltmode?
resistors to change what and how many ohms are?

sorry for my bad anglish

[marcooxx]

marcooxx, what do You mean? For Vmem You have to hard-mod also.

Yes hard mod ok if is possible

[marcooxx]

I have made the voltage mod :
880 mhz vcore 1,45v
1000 mhz ram
temperature vcore 72 c

Stock dissi vapor

But with more voltage can rise again

[Factotum]

Does anyone know how to make Vmods on Asus 4870 Glaciator PCB? This PCB got 4+2 phase.

Asus EAH4770 non-reference PCB:




help me more please
FB to VR, VR 100kOm to GND, or otherwise?

[ceemic]

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