9800XT vmods

**bmg** · 10-21-2003, 12:51 AM

I started a couple of threads in the Overclocking forum about the 9800XT vmods. Perhaps I should copy the information to this forum, but for now I'll just post the links:

Vdd memory voltage mod:
http://www.xtremesystems.org/forums/...threadid=20855

Vgpu voltage mod:
http://www.xtremesystems.org/forums/...713#post248713

Check runmc's post below this one for some good pictures. Also,
here's a link to a pretty good picture by jvlk showing the mod and measurement points.
http://www.3dmaxx.net/forums/showthr...=&threadid=645
Save the pictures and then you can zoom in to see the details.

**runmc** · 10-26-2003, 12:35 PM

The reading is very good. Maybe I can figure it out by looking at my card, your card, and your directions.

ron

ddr volt-mod

A working GPU Mod.. Credits to bmg.

**CCC** · 10-26-2003, 03:26 PM

i agree with runmc, definately thanks alot for the guide but if there is any way you can take some clearer pics that would be great

THANKS

**CATCH22ATPLAY** · 10-28-2003, 10:21 PM

Voltage select pins are your friends. Why don't you just use them. So long as you don't mind cutting a leg or 2 off the chip. I wouldn't be opposed to that. I was thinking about just connecting vid2 to vid 1. But doing the math with your excellent calcs that would equal 2.026 volts. Hmm i ran my R9800Pro that high once. But i did have -150F cooling at the time. Still it didn't like it that high. So i wouldn't recomend that at all. If it was me i think i'd just cut vid 1. Then connect vid 2 to vid 4. That would give you 1.90 even based on your calcs

But i'm a crazy bastard so don't do what i say. hehe

btw my edit was to change my last line from do what i say to don't do what i say. I hate when i fry other peoples stuff

**sadcat** · 10-29-2003, 12:47 PM

Thanks bmg for sharing the 9800XT mods. I just got that card. The vdd mod was very clear, but I would like to ask about the vgpu mod. It appears the black wire is on #1597 not #1591 and the red wire is on #1592. The 7 is cut off by a hole in the board. Is this correct? Also which wire is on the vr and which goes to ground? I really appreciate your help! I'm a homebuilder and I'm electronically challenged. Thanks!

**bmg** · 10-29-2003, 03:54 PM

Originally posted by sadcat
Thanks bmg for sharing the 9800XT mods. I just got that card. The vdd mod was very clear, but I would like to ask about the vgpu mod. It appears the black wire is on #1597 not #1591 and the red wire is on #1592. The 7 is cut off by a hole in the board. Is this correct? Also which wire is on the vr and which goes to ground? I really appreciate your help! I'm a homebuilder and I'm electronically challenged. Thanks!

It's hard for me to tell if it's a 1 or 7, but I think you're right that it looks more like a 7. In any case it's the resistor above R1592.

If you look at the board you'll see that R1592 and R1597(?) are connected together, so it didn't matter which one I soldered the red wire to. Note that the wire connected to the ground end of R1597(?) could be connected to ground any other place that's convenient. The other connection should be ok if you've got a very small tip on your soldering pencil, use a small gauge wire and pre-tin it with solder, and then apply heat to the wire, not the resistor, and remove heat as soon as the solder melts. I usually do this sort of thing in at work where I have access to the correct equipment for working with tiny parts, but in this case I had no problem doing it all at home.

Soldering directly to one of the 5240 leads seems riskier, due to the size of the leads and the spacing. I haven't used smd grabbers like others use, but maybe some are available which would work with the small leads and spacing. Just be sure that it doesn't short two of the leads together.

The bare round pad between R1592 and R1594 would be another possible solder point, but that almost seems riskier than soldering directly to the resistor, unless you have the proper equipment and a steady hand.

**runmc** · 10-29-2003, 07:28 PM

thanks bmg

Would it be possible to solder red wire to R1592 and black wire (ground) to fan ground pin sticking through the card. That would be safer for me. It would be one less resistor to worry about.

Also if you soldered to R1592 on the side close to the small pad and soldered to both the resistor and pad, would that be O/K.

**bmg** · 10-29-2003, 09:34 PM

Originally posted by runmc
thanks bmg

Would it be possible to solder red wire to R1592 and black wire (ground) to fan ground pin sticking through the card. That would be safer for me. It would be one less resistor to worry about.

Also if you soldered to R1592 on the side close to the small pad and soldered to both the resistor and pad, would that be O/K.

Yes, that sounds like an excellent way to do it. I didn't think about using the fan ground pin. Just making one solder connection to the resistors cuts the risk in half, so that's good. As long as your wire is small, you apply heat to the tinned wire and not the resistor itself, and you have a good soldering pencil with small tip, you should be ok. I can't see the need to connect to both the resistor and pad.

**runmc** · 10-30-2003, 04:05 AM

Thank you for the quick response, that helps very much. We appreciate you sharing your knowledge.

Keep your fingers crossed for me lol

**sadcat** · 10-30-2003, 04:26 AM

Thanks for the quick answer! One last question if I could. Where have you found a good measure point? I hate blindly hunting around in there with a meter. Thanks yet again.

**runmc** · 10-30-2003, 05:58 AM

bmg.

I edited the gpu mod picture. Could you check it for me to make sure it looks o/k.

Did I mark the checkpoint correctly?

thanks ron

**bmg** · 10-30-2003, 08:22 AM

Originally posted by runmc
bmg.

I edited the gpu mod picture. Could you check it for me to make sure it looks o/k.

Did I mark the checkpoint correctly?

thanks ron

Looks fine. It was nice ATI left solder mask off that one measurement pad.

**runmc** · 10-30-2003, 02:05 PM

Looks fine. It was nice ATI left solder mask off that one measurement pad.

Cool

Now for the nitty gritty..

**bmg** · 10-30-2003, 05:15 PM

Originally posted by runmc
Cool Now for the nitty gritty..

Let us know how it worked out.

**charlie** · 10-31-2003, 02:15 PM

anxiously waiting....

C

**Nohto** · 11-04-2003, 07:03 PM

Originally posted by runmc
thanks bmg

Would it be possible to solder red wire to R1592 and black wire (ground) to fan ground pin sticking through the card. That would be safer for me. It would be one less resistor to worry about.

Also if you soldered to R1592 on the side close to the small pad and soldered to both the resistor and pad, would that be O/K.

The center pin on the fan ground does not ohm out to a ground. Are yiu sure that this is the correct location for the second wire?

**runmc** · 11-04-2003, 08:35 PM

Unfortunately my v-mods were not a proven success. I didn't get to try them, as my card fell to condensation. The fan ground wire was merely a suggestion. It was not proven.

I have removed the gpu mod pic as a precaution that no one will try it, as it was not proven.

Thanks for the heads -up Nohto

**bmg** · 11-05-2003, 10:13 PM

Bummer about the card.

I checked the 3 fan connector pins this evening and none appears to be a ground. Too bad as that would have been an easy connection point.

**~~AdultSwim~~** · 11-12-2003, 12:14 PM

yeah that sucks

**Holst** · 11-12-2003, 12:17 PM

Originally posted by runmc

Unfortunately my v-mods were not a proven success. I didn't get to try them, as my card fell to condensation. The fan ground wire was merely a suggestion. It was not proven. I have removed the gpu mod pic as a precaution that no one will try it, as it was not proven.

Thanks for the heads -up Nohto

I wouldnt recomend that anybody use a fan header as gound on a graphics card.

If you absolutely cant find anywhere then you have a perfectly good ground at the power connector.

**bmg** · 11-12-2003, 12:35 PM

Originally posted by Holst
I wouldnt recomend that anybody use a fan header as gound on a graphics card.

If you absolutely cant find anywhere then you have a perfectly good ground at the power connector.

None of the 3 pins on the fan connector was a ground.

**charlie** · 11-13-2003, 06:22 PM

Strange....
I did my Vgpu mod that way and it seemed to work!
With the ground on the center fan ground that is...

C

**charlie** · 11-13-2003, 06:37 PM

Since there's no piccies around....is it agreed that this IS the Vgpu MOD????

C

**CATCH22ATPLAY** · 11-13-2003, 07:31 PM

Yes you did it correct in that the right side of R1592 and or R1597 is to be connected to ground. Doesn't matter which resistor you use. Both the right sides of them resistors are tied together on the right side. Soldering from the right side of R1592 would actually be the more correct way because the left side of that resistor is connected to ground. So for a resistor divider network you picked the perfect. I haven't check the center pin on the fan header though. Wish someone would ohm that pin out with power off and see if it really is ground. Seems it might be. But just because the mod works doesn't mean it is a ground. What if it's being used to speed up or slow down the fan? But it is a black wire. So i'd guess it's a ground. Luck on mods dudes. I'm running my GPU at 1.925 atm and will increase to 2.00 and see wtf happens. 533 core just isn't cutting it. BTW i do my mods quite a bit differently. Er the old pencil method hehe. LOL is that cheap or what? Check resistance on the right side of R1597 to ground. Pencil in R1597 and check the ohmage again. You can also pencil in R1592 for the same results as well. Be careful because going from 330 to 313 gets my gpu to 1.925 volts

**runmc** · 11-13-2003, 08:01 PM

I just posted pics in the sticky and the 9800XT mod thread

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