Most bang for the buck - CPU or GPU upgrade?

[Vahnu]

APPROXIMATE PURCHASE DATE: End of this week.
BUDGET RANGE: USD $150-250 Before Rebates

USAGE FROM MOST TO LEAST IMPORTANT: Mainly upgrading a 2007 system build to play World of Warcraft at High to Ultra settings. Will be upgrading everything eventually however need to know what to upgrade first. Budget will not allow to upgrade all at once.

CURRENT GPU AND POWER SUPPLY: EVGA GeForce 8600 GTS Video Card - 256MB GDDR3 on a 400W PSU

OTHER RELEVANT SYSTEM SPECS: AMD Athlon 64 X2 3800+ Processor ADA3800DAA5CD - 2.0GHz, 1MB Cache, 1000MHz (2000 MT/s) FSB, Toledo, Dual-Core, OEM, Socket 939, Processor

Asus A8S-X Motherboard - SiS, Socket 939, ATX, Audio, PCI Express, Gigabit LAN, S/PDIF, USB 2.0, 4GB RAM


PREFERRED WEBSITE(S) FOR PARTS: Amazon, TigerDirect, NewEgg
COUNTRY OF ORIGIN: USA


PARTS PREFERENCES: Open to suggestions. ATX case is what I currently have.

OVERCLOCKING:No or Maybe. With the older hardware, most likely not. SLI OR CROSSFIRE: No

MONITOR RESOLUTION: 1680 x 1050 currently

ADDITIONAL COMMENTS: I know this is an older computer however would like suggestions rather than just replace everything. Mainly, is it better to buy a new GPU or CPU first?

Thanks for tanking a look and would appreciate any and all suggestions.

 

[ihog]

To buy a better processor, you also need a new motherboard. Depending on what graphics card you're looking at, you might have to upgrade your PSU as well.

I'd go the graphics card route first, but you might be held back by your processor.

 

[Vahnu]

I was looking at getting ::EVGA GeForce GTX 750 Ti Gaming Graphics Card - 2GB GDDR5, PCI-E 3.0 16x -

Just concerned that with the older mobo and processor if I would get a bottleneck as this may be too much video card for the older system.