Can I use an Opteron 64 X2 CPU on an Athlon 64 X2 Motherboar

X2 Manchester Core 4200, 4600 & 5000 = 512Kb L2 Cache - fair choice.

X2 Toledo Core 4000, 4400, 4800 & FX-62 = 1Mb L2 Cache - good choice.

Opteron Denmark Core 165 thru 185 = 1Mb L2 Cache - best choice.

Although the dual core 165's thru 185's are marketed as Denmark cores, CPU-Z will identify them as Toledo cores, which is the same core as the X2 4000, 4400, and 4800. Essentially, the 939 X2 4000 @ 2.0Ghz (if you can still find one) is the desktop counterpart of the Opteron 170 @ 2.0Ghz. The Opteron 1xx series have 1Mb L2 cache per core, and they use standard DDR unregistered, non-parity memory, so the only difference other than price, is that the Opteron is a server / workstation class processor.

Opterons are more stringently fabricated, tested, selected and binned for stability, and are yielded from "cleaner" silicon semiconductor material. They operate at lower voltages and temperatures per clock, as compared with their X2 desktop conterparts, which make the Opterons the best overclockers. The 170 is statistically the highest overclocker, often achieving 50% on high end air cooling, depending upon stepping.

The overclocking limit for clean 90 nanometer dual core AMD's is about 3.05Ghz. Of course, they're all unique, and there are always exceptions. My previous rig was an Opteron 170 @ 3.0Ghz. It's an excellent CPU, and an inexpensive equivalent to the 2.8Ghz FX-62 Flagship chip. Opteron 170's are currently selling for $184.99.

http://www.newegg.com/Product/Prod [...] 6819103586

Hope this helps, and good luck!

Thankyou, I do plan on an X2 Opteron.