better cooling can help to get a better overclock, tho from my experiences it helps the most with the memory, without a volt mod the core seems to pretty much max out on the stock cooling on most cards, might get an extra 5Mhz... I can't really advise volt modding tho unless your prepared to replace the card soon.

I'm using it in a shuttle so clock's aren't mega but I whacked it into my brothers old system XP3200+ with a decent sparkle psu and the Asus hit 455/1.2 ghz sweet ! now I just need to find a heftier psu for my shuttle and it's play time. hmmm wonder what it'd do on water 
zoink