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Radeon HD 4850 Voltmods

wizzard, is the smd capacitor that you are showing on the vgpu voltage mod ground?
 
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thx
 
How are the overclocking results with these mods? Does it help the poor overclocking issues any?
 
the big yellow cap on the left side of the vgpu mod is gnd
 
I'm thinking about doing the pencil mod (for the first time since the days of Duron)
I'd like to have a bit more information if possible.

1. What kind of pen to use?
2. How much do you shade with the pen?
2.5 As I've understood the more shade the less resistance and thus higher voltage. Correct?
3. Do I need a Digital Multimeter to measure the VDC+resistance (I'd rather not at all)
4. Do I need to download a new firmware to the card? If so, then where? (Ordered a Sapphire 4850)

Thank you for your hard work :)
 
#2 pencil and a multimeter.

- Christine
 
Thanks for the replies. I guess I have to chicken out then... :(
 
Thank you, W1zzard!

Is there already any software to manipulate the VGPU under Windows when I have done this Voltmod? Or is it necessary to flash the bios for each alteration?
 
Just connect the two solder dots the pencil point is pointing at to short that out? Seems easy enough, but was wondering why only one picture actually shows a line drawn between the points? I guess it has something to do with the "paint"?

Anyways wonderful guide!
 
the line in the picture is to clarify that you have to pencil between the points across the pcb. usually you pencil on a component like a resistor
 
Thats what I thought, thanks for clerifing.

Im dead in the water right now with both my 4850's I think a bad bios flash, or corrupted drivers. O a combo of both the bios flash made the drivers go fubar.
 
I know that this is an ubernoob question, but how do I measure the VGPU voltage? I'm guessing it doesn't matter where the + and - leads go, just at one any one of the points. Am I correct?
Can someone also post some benches of their new overclocks as well?
 
What kind of pencil would I need to do a pencil mod?
 
ShadowFold said:
What kind of pencil would I need to do a pencil mod?
Click to expand...

A good 2B or 4B pencil. I used my Faber Castell 2B pencil. Strangely enough, my 4B pencil doesn't decrease resistance at all, only adds to it, so always have an alternative at hand.
 
DavyGT said:
I know that this is an ubernoob question, but how do I measure the VGPU voltage? I'm guessing it doesn't matter where the + and - leads go, just at one any one of the points. Am I correct?
Can someone also post some benches of their new overclocks as well?
Click to expand...

you put the red probe to the measure point and the black probe to any ground which could be case metal, molex connector black cable, pcie power plug gnd or a million other spots. the grounds are all connected with each other
 
another uber noob question: how much wattage for the resistor? i found various 100k ohm variable resistors, but they come in different wattages.
 
Any ideas on how long the pencil would stay on there for once modded? Never done this before and don't want to have to keep applying every two weeks, thanks.
 
so for that first pencil mod are we putting it on top of that one already filled or the empty one next to it?
 
no worries, all sorted. Now at 790/1180 stable :) £117 quid well spent
 
hi guys.. quick question if I use the first pencil mod.. which only alows 1.4 volts (no more).. does that mean i can actually just pencil as much as I want without worrying overvoltage? (no need a dmm)?
 
Yes, I think you can't kill your card with the first pencil mod, but everything depends on your cooling. If you have a good aftermarket cooler, you don't have to worry about anything. But if I were you, I wouldn't do this without DMM.
 
I got an accelero on it and i get 38 ide 45 load.. what do you think sufficient?
 
If you have Accelero S1 on it, then you can try that pencil mod. But remember to check temperatures all the time, especially #2.
 
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