the retail heatsink has bean take off, the chip will most likely
be full of glue residue. Also, some chip aren't flat, Nvidia
is famous for that. These are two good reasons to lap your chip.
Lapping your chip means to sand it off. This will take all residues
out of the way and if done right, will make your chip perfectly
flat. It will also reduce you chip temperature further since
the heatsink will be closer to the chip core. Start by surrounding
the chip with electrical tape to prevent any debris to get stuck
in the board circuits. Then, start sanding. Be patient, this
is a long and unpleasant process. I was sweating like hell while
doing this, continuously asking myself if I was helping or killing
my video card. Here are a couple of pics I took in the process.
carefull not to sand too much. I stopped to sand once I couldn't
see the Nvidia logo on the chip anymore. To clean the chip,
you can use a small quantity of alcohol or nail polish remover.
Just make sure the chip is perfectly dry before installing your
new VIce heatsink.