Legit Reviews posted a review on the AMD Athlon II X4 635 2.9GHz Quad Core Processor. Here's a taster:

Despite not offering any new features or mind blowing performance, the AMD Athlon II X4 635 is a solid product. It was able to keep up with both the Phenom II 940BE and the Phenom II 910e in just about all of the benchmarks performed today. Pair the Athlon II X4 635 with a motherboard like the MSI 785GM-E65 and for a little over $200.00 you can have a solid base for great computer. Not bad, considering the system would support dual-monitors, Blu-Ray playback, GPGPU applications like stream and most importantly it would be ready for Windows 7.

One item I would like you to take note of in case you haven't already is the voltage. While the voltage rating for the Athlon II X4 635 is .85-1.25volts it defaults to ~1.4 in the bios and can be seen in CPUz as 1.392 volts. I wanted to see if it would run at the factory speeds while within the factory voltage range. After firing up into the BIOS I set the CPU voltage to 1.24v and left every other setting on auto. It is Prime 95 stable for 24 hours. Something else happened while running Prime 95, the load temps dropped dramatically. While at the default settings, a run of Prime 95 brought the processor up to 45 degrees Celsius. With the lower voltage the Athlon II X4 635 is only hitting 35 degrees Celsius. That is a 10 degree drop! While a BIOS update may be required for for this particular motherboard other motherboards may not have this issue.