Which GeForce 8800GT 512 should I buy?

Lots of models because they're all based on the same reference board and perform identically, so manufacturers try to differentiate themselves to stand out from the crowd.

The KO and OC models are overclocked and will perform a bit faster than other models, in the range of 5% usually.

Another factor is the bundle, look to see if any include a game you plan to buy.

G80 is the old one and G92 is the new one, which is much faster. 512 or 256mb models are the new ones, 320 or 640mb models are the old ones.

yabyab, they do not overheat. they can become hot. I got EVGA 8800 GT on Monday. The BIOS has a bug in it and the fan stays at 29% speed. I downloaded free NTune from nvidia.com and increased the fan speed to 50% and it stays cooler now. All 8800GTs are G92. 8800GTX and 8800GTS320/640 are G80. Make sure you get EVGA one, they bundle the best game ever made (Crysis IMHO) and offer lifetime warranty as well as superior customer service and message board. You won't be dissapointed.

This is worth reading

http://www.tweaktown.com/articles/ [...] index.html

Ya can see here that the newer G92 runs from $359 - $389....one comes with a copy of Crysis.

http://www.newegg.com/Product/Prod [...] 92&x=0&y=0

One thing I always consider fro support and compatibility reasons is the MoBo. For example, if I have an Asus MoBo, I'm likely to lean to an Asus board if for no other reason that TS can't tell me to call the MoBo vendor for a solution

BTW, some vendor's have OC'd versions, Asus was the 1st out of the gate with their "TOP" verison which is overclocked from 650 to 740. BFG overclocks theirs from 650 to 675.

Here's a comparison of the Asus versions

http://www.asus.com/news_show.aspx?id=9233

And more info

http://www.hardwarezone.com/articl [...] =3&id=2436
http://www.xtremesystems.org/forum [...] p?t=169082

Though Asus was 1st to 'announce" it was shipping an overclocked version, I haven't actually seen it in the channel anywhere as yet.