How do you effectively lap a video processor??

[ahsumdude]

I have a Gainward GF3 Ti 500 that can reasonably do only 255 in 3Dmark 2001 and remain stable after several loops. I replace the original cooler and notice a thick layer of "goo" on that orb cooler that appeared not to make contact with the center of the GF3 chip. I lapped the cooler I replaced onto the card and now can do 270 stable in 3dmark 2001. I feel this chip can do more if I could effectively lap the core and remove the concavity of the chip. Does anyone have a clue to efectively lap this "bad boy"?

 

[Bozo Galora]

dont do it. I ruined two Gforce trying to lap that thing. If you put the card on a surface plate with a test
indicator one will find that they are all concave as you say from .0015 - .002. While that doesnt seem like much ,
its critical to cooling. If it were convex it would be no sweat, since most of heat is in middle. The slightest
sanding gets you to the danger zone. After doing one perfectly flat, I had garbled grey and white artifacts at
bootup. Tried flashing the bios 6 different ways, couldn't bring the card back. Thinking I might have got static
electric damage, I did another one and ruined it too.
I learned my lesson.

 

[ahsumdude]

Alrighty, that solves my question. I will heed your advice and gain knowledge from your wisdom! Leave well enough alone!!

I have in the past year toasted an A7V133 with a bad volt mod--bummer!
I have fried an XP 1900 when changing MB's and not realizing the HS was askew--another bummer. All this in search of the holy grail for more power!

Thanks for the insight buddy!!
I'm getting 15 Mhz more out of the GF3 with just changing to a better cooler. I'll take that!