Like svol said, it's good for if you want to overclock the vid card, but does not provide any actual performance increase on its own. It may drop your case temp by a degree or 2 and may prolong the life of your vid card as well (unless you install the heatsink incorrectly, which will drastically shorten the life of your vid card). My advice? don't bother unless you're planning on overclocking it or using it for more than 2 years, and don't do it at all if you don't know what you are doing.
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