The flat copper area that rest on my gpu is a little uneven. Instead of flat there's a small sharp ridge. It was running hot and i'm repasting but wonder if i need to make this very flat too, like sand a bit. Thanks.
NO amount of paste could replace a smooth surface. You can use sandpaper (extra fine) to polish away that ridge and smooth the entire surface. Place the paper flat on a hard surface then use gentle motion to move the block on the paper, using only the block's weight to press down. Wet the paper for best results.
Whoa.....before taking sandpaper to it...is it actually uneven?
Sandpaper it, and you've probably toasted the warranty.
unfortunately its too late for that although..i should have thought it through more. I'd prefer not to have to rma it but you're right if I can't fix the problem I should wait on these things. thanks for all the feedback.