ATI 4850/4870 voltmod thread

[8800's@over]

No, none, sorry (very low ohmage needed, and no solution as of yet).

More exist without the other point for the current Pencil?

I have as a welding wire in the current point with conductive ink?

[scutzi128]

Hey ceemic on that asus 4850 what points were you using to test for the vcore voltage?

[Jim M0rrison]

More exist without the other point for the current Pencil?

I have as a welding wire in the current point with conductive ink?

Im not really sure what you are trying to ask in the first sentense? I any case, Ill repeat why a pencil-mod isn't viable on the reference 4870: The resistance from the soldering point to ground is really low. With a potentiometer of the right range, you can still navigate a "parallell" ground connection within the right ohmages, creating the desired drop in voltage at the soldering point.

You can easily attain a rather stable 10Ohm with the correct potentiometer, but trying to get a controlled resistance of that magnitude with the stroke of a pencil is really hard.

EDIT: If you meant to ask if there are other points for the pencil mod, I don't know, and I woulnd't bet on it. But soldering is so much more fun anyway, right?

[ceemic]

scutzi128, http://ceemic.pri.ee/hardware/hd4850..._mod01_mon.jpg

[scutzi128]

Thank you very much. It's just one of those to ground correct?

[ceemic]

scutzi128, yes, You can use one of them. Just put You DMM's black wire (GND) to some GND in Your PC (molex GND is also OK) and red one to that point...

[scutzi128]

Your the man thanks a bunch.

[@lex]

About non-reference ASUS 4850: it doesn't have VRM cooling. Is it safe? Should I place a heatsink there for VM or 120mm fan would be enough?
Would I face any difficulties changing cooler to Accelero S1? I don't want to disassemble it while i'm not sure i can revert all of my modification to factory original state...
Thanks.

[ceemic]

@lex, yes You can use AC S1, and I recommend it. It is very good perf/buck value and I have the same cooling on my 4850 with 2x120mm fans. I used the VRM heatsinks also, because whole PWM gets pretty hot under load.

[@lex]

@lex, yes You can use AC S1, and I recommend it. It is very good perf/buck value and I have the same cooling on my 4850 with 2x120mm fans. I used the VRM heatsinks also, because whole PWM gets pretty hot under load.

Thank you very much for advising noobs like me!
I've got 2 last(for now) questions:
1. Will I be able to install original cooler back(leaving no evidence of changing it)?
2. How do you think, is the card's VRM reliable enough? Will the card survive moderate voltmod for 24/7 using?
Thanks again!

[ceemic]

Sorry, I can't help You with the RMA case, when You plan to Vmod Your card. Even changing original cooler voids warranty. Tho, I don't know, if they will examine the thermal paste, when the cooler has been canged.

Good luck!

[Bluto05]

I have an AC S1 on my 4850 and it is an amazing cooler for the price. I strapped on two 92mm 55cfm fans and my load temp using furmark is 44C @ 24C ambient temp.

[joshua7]

Guys, anyone having info on vmodding a Gainward HD4850GS? Or some clever bios available? Don't wanna do a hardmod, just like a simple bios, or something.

[ceemic]

joshua7, Golden Sample cards probably have the highest possible Vcore in BIOS so I'm afraid You can't do much about it.
If You dare to do hardmod, You can look my work: http://ceemic.pri.ee/hardware/hd4850gs/

[noinimod]

kinda pissed that my asus 4850 hsf doesn't cover the PWM area.. might have to change it soon

[Jimbo Mahoney]

My 4830 has almost the same chip as the picture in the first post shows:

uP6201BQ

but the second line is different.

Will the voltage mod be the same? i.e. 100k VR from top right pin (or other point connected directly to that pin) to ground?

EDIT - Also, my 4830 default 3D voltage seems to be 1.26v. It does 775 Mhz easily. Is this normal?

It ties in with the speeds / voltage this guy had on his 4850:

http://forum.beyond3d.com/showpost.p...postcount=4695

e.g. 775 Mhz @ 1.26v

[ceemic]

Jimbo Mahoney, other markings on IC are irrelevant. Yes it is the same pin 13

[@lex]

775 Mhz @ 1.26v

It's typical result, am I right?
I have now my second ASUS 4850. First was reference, it was hot like hell and I killed her by changing cooler. I've done pencil mod and I had 765 MHz max stable @ ~1.32V. Why such low result?
MEMIO temp. was 61C max at ATITool.
With Accelero S1 and voltage set to 1.18V it was stable @715-720 MHz(685 only with ref. cooler).
Like i said, I've killed that card and I'm very unhappy about it.

They've replaced it for non-ref. 4850 I described earlier. It has Glaciator fan which I didn't touch yet and it's stable 725MHz@1.18V (software), but the temps are high enough (MEMIO > 86C).
Is it worth overclocking?
Why do I have such low gain from VMod?

P.S. Shouldn't we create topic for collecting 4850/4870/4830 OC statiscs?

[Jimbo Mahoney]

Jimbo Mahoney, other markings on IC are irrelevant. Yes it is the same pin 13

Thanks ceemic!

It's typical result, am I right?

Not necessarily - I'm using water, so probably much lower temps, which help too. I'm just suspicious that my 4830's default Vcore is 1.26...

[joshua7]

joshua7, Golden Sample cards probably have the highest possible Vcore in BIOS so I'm afraid You can't do much about it.
If You dare to do hardmod, You can look my work: http://ceemic.pri.ee/hardware/hd4850gs/

Yeah, saw those pics, but I will definitely not do that.

[ceemic]

joshua7, why not?

[regenade]

A detailed pic of the voltage controller region on the Powercolor HD 4870 (new analogue VRM version)

[Jim M0rrison]

A detailed pic of the voltage controller region on the Powercolor HD 4870 (new analogue VRM version)

Hey regenade, we have the same card. Look at my post (#1250). I posted a picture there for the vGPU soldering point. When I measured the resistance to ground, I got 16kOhm, but I didn't have a 200kOhm vr at the time. I have still not been able to test with a vr.

So, regenade, could you please measure the resistance of your card's FB->ground, according to the picture in post #1250? Would be good to have it confirmed.

[regenade]

Sure will report it once I get back to home
Btw since its a 16k ohm....wont some pencilling work on it :P

[Jim M0rrison]

Sure will report it once I get back to home
Btw since its a 16k ohm....wont some pencilling work on it :P

Great!

Well, tbh, I never saw the point of pencil modding. I want to set the optimal vGPU by running ATitool or something, clocking and adjusting the vr "live", to find the best balance between clocks, voltage and heat. This is ofc not possible when pencil modding.