Not how it works, it's usually a scam that ebay sellers pull on people to try and make them think the CPU is 6.4Ghz, it's not, it's just a 3.2Ghz dual core.
As for what games, tough one. It's not capable of playing the really demanding games at all, so say Crysis, Rainbow Six Vegas and Supreme Commander:Forged Alliance, but all other recent games it could handle at low settings, you know, 800x600 low detail, 640x480 Medium, that sort of arena. In other words, it can play most games but not all, but only at awful detail settings.
Those components themselves are worth about £220 or so. £300 is quite a lot as they're all old components (except for the drives). You could build a far better PC yourself for that money, but you're not going to find something that beats it in a PC world shop.
