Here are the list of supported CPUs for your motherboard:
This can be checked from the link below:
Use Intel Site http://ark.intel.com to compare the CPU features and based on that you can opt for the most appropriate CPU.
All the best,
I have a little problem, this is the computer i bought two months ago:
DualCore Intel Core 2 Duo E8500, 3166 MHz
Asus P5QD Turbo (2 PCI, 3 PCI-E x1, 1 PCI-E x16, 4 DDR2 DIMM, Audio, Gigabit LAN, IEEE-1394)
4 GB DDR2-800 DDR2 SDRAM (6-6-6-18 @ 400 MHz) (5-5-5-15 @ 333 MHz) (4-4-4-12 @ 266 MHz)
NVIDIA GeForce GTS 250 (512 MB)
I can't just change it all again, it's too expensive! I think I'm going to buy a quad core.. or maybe a new video card.. but I think that the processor is more important.. thanks you very much!
If you're "upgrading" only for gaming, then don't get a quad-core: The processor by itself would very likely be way too expensive for whatever performance improvement it delivers; in fact, the quad-cores would actually be a downgrade from your current E8500 on games which cannot make use of more than two cores simply because they run at a slower clock speed than your E8500 (even the fastest non-Extreme Core 2 Quad, the Q9650, runs at only 3000 MHz versus the 3167 MHz clock speed of your E8500 - and the Q9650 by itself is way too expensive at current street prices, considering that you can buy an entire new i5-750 platform for a little bit more). Instead, concentrate on getting a better graphics card (the GTS 250 is old by current standards, having been first introduced as the 8800GT 512MB, which uses the exact same GPU as the GTS 250 but with slightly lower clock speeds, two and a half years ago).
On the other hand, if you're into video editing/encoding, then a quad-core might improve performance.