Help! my 4870x2 is not performing up to it's standard

[arcane_127]

Hi, here's my problem :

I've recently upgraded my graphic card from Nvidia 8800GT to ATI 4870x2 and tested it with crysis warhead. I keyed in the playable settings I previously used for my 8800GT ,but it's not smooth.
Note: game tested using windows xp
(Very High, 1440x900, AAx2 - not smooth)

My computer specs

Intel Core 2 Duo E6750@ 266Ghz
Gigabyte EP35-DS3 motherboard
Sapphire ATI 4870x2@ 2GB VRAM
4GB RAM,
Vista Ultimate 32-bit/Windows XP Professional 32-bit (Dual-Boot)

Should I get a better motherboard and processor?

 

[arcane_127]

ahhh i'm planning to go for a new motherboard - ASUS P5Q3 with ATI support PCI-E slots and maybe an E8400.. hopefully it will do well in this case.. because i'm already very disappointed