Passively Cooled Graphics cards

I Have a 8500 GT which has got a fairly large heatsink covering its front completly, with fin like things, its fairly heavy but am i likely to find problems when playing games, you know when it overheats?

if that makes no sense then

Passively cooled graphics cards, good or shit?

if someone could reccomend a cooler that works on 8500 series nvidia cards that would be nice =], since i know how to fit zalman shit to cards, just havent found a 8500 series compatable one yet

shit

Why would they make it passively cooled if that weren't enough for normal use (including gaming)? Mine works just fine.