The biggest difference seen isnt the quality of tim used but the quality of the application of the tim. With my 2 9800GTXs 1 was down very well while the other had TONs of tim everywhere and when I re applied my own tim it brough the temps down almost 9c at load.
The nvidia cards are fairly straight forward to take appart, remove 1-2 screws that hold the PCI-E plate to the back of the card, then remove up to 15 spring loaded screws holding the heatsink to the PCB, they may not be spring loaded and they wont fly out at you if they are the springs are used more like a washer to hold more tension on the PCB. Probubly the easiest process involving tools ive done in a while and well worth the 10 minutes of effort. Once you get the heatsink off all you have to do is clean off the top of the GPU with an cleaning solution or do like I did and just clean it off with a Q tip and call it good enuf, then reapply the new paste and screw on the heatsink again. The Memory will more then likely use a thermal pad instead of paste and its not recommended to remove these and try thermal paste as it will take far to much paste to bridge the gap left by the thick thermal pads.
http://www.hardwarecanucks.com/forum...retim-ic7.html
My worklog from when I did my 9800GTXs.
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