Upgrades...advice required...

Current Alienware system is as follows...

AMD Athlon(tm) 64 FX-53, Socket 939
ASUSTeK A8V Deluxe
RADEON X800 XT Platinum Edition 256MB (AGP)
4 x 512MB DDR PC3200 (333 Hz)
XP Home Edition (fully patched)

18 months ago this was 'the dogs' (apologies for UK slag, it means it is/was rather good). Am now starting to look at upgrades to system but keeping the exisiting mobo/case/cooling if possible (as I am lazy).

Considering AMD upgrade (Dual Core?), memory upgrade (4GB perhaps) and an updated AGP card. Anybody got any suggestions, specificially regarding the AGP card, will blowing some cash get me much more performance or will it only be a marginal improvement (due to bottlenecks etc). Where will my cash be best spent?

Performace required for next generation of 3D shooters and Vista (am aware current system will cope fine with Vista).

Any advice/comments appreciated

Regards

Clarkie 8)

A decent XFX GeForce 7900 GTX 512 MB will double your 3D performance.

The GeForce 7800 GT/GTX are power burners, and 'older' now, possibly even more exensive than the 7900 series (which is cheaper to make, and faster, smaller die, smarter design, less power usage, etc).

You'd need a mainboard with PCIe x16 (PCI Express Graphics x16 slot, sometimes called PEG x16).

PCI-X is not PCIe, and is actually different slot.
http://en.wikipedia.org/wiki/Image:64bitpci.jpg

Keep the FX, get a new mobo and gfx card. The card I would go for today is the X1900XT. I would also look at the Asus R580 mobo.