Overclocked Intel Core 2 Quad Q8400 2.66GHz @ 3.20GHz
Gigabyte GA-EP45-UD3LR Intel P45 Motherboard
2 x Corsair XMS2 2GB 8500C5 DDR2
ATI Radeon HD 4870 1024MB GDDR5 PCI-Express Graphics Card
Western Digital Caviar Black 500GB SATA-II 32MB Cache
Should I go for an additional graphics card? If so, should it be the same as my current one, a similar model, or doesn't it matter?