I have been running AMD processors for some years now preferring them over Intel on initial cost but moreover the performance.
I have used my MSI motherboard to test various AMD processors from the meagre 2ghz single core and upwards using both the single core and the X2 ( dual core) processors in 2.2ghz, 2.3ghz,2.4ghz and 2.6ghz with impressive results.
I don't use my pc for gaming or anything like that, but make extensive use of the internet as a workhorse to evaluate computer hardware.
For the last 6 months I have been running an Athlon 64 2.6ghz single core processor on an MSI board. The performance has always been exceptional.I am now running an Athlon 64 2.6ghz X2 ( dual core) processor with impressive results, the cpu barely breaks into a slow trot, and shines like a distant galactic star when I give it some work to be done. It makes light work of heavy internet use, and uses about third of the power resources it has available.
When considering a processor, give the AMD Athlon 64 Single cores some serious consideration as an inexpensive power horse for your pc. Going on from that, give the X2 ranges of processor from 2.2ghz upwards a place inside your pc. You will be impressed.
As a guide, I have found that a 2.2ghz X2 performs about the same as a 2.6ghz single core, and a 2.6ghz X2 ( dual core) blows away just about anything Intel has to offer. This 2.6ghz X2 will outperform an Intel Pentium 4 3.6ghz processor, and to match the performance to an Intel is difficult at the best of times as Intel don't have anything that is in the same clock speed that gets even close to matching it.
My recommendations, go for Amd over Intel any day