AMD Athlon II X4 630 = $100
Those looking for a cheap quad-core processor will love what the AMD Athlon II X4 630 has to offer. This 2.8GHz quad-core model supports the latest AM3 and past AM2/AM2+ sockets and amazingly costs just $100. The Athlon II X4 630 model was selected as it is just a few dollars more expensive than the 620 which is clocked 200MHz lower.
The Athlon II family differs from the more expensive Phenom IIs primarily on its lack of a L3 cache. While the L2 cache is still just 512KB per core, the 6MB shared L3 cache of all Phenom II processors has been disabled. This should have a considerable impact on performance, though at $100 the Athlon II X4 630 still represents an exceptional value.
AMD Phenom II X2 555 = $100
At the same price point the Phenom II X2 555 Black Edition is AMD's most expensive dual-core part. It is clocked at 3.2GHz and receives the full 6MB L3 cache. The chip is essentially a Phenom II X4 with two cores disabled, which means that with the right motherboard and BIOS configuration it is likely that these cores can be enabled back, turning the $100 Phenom II X2 555 into a Phenom II X4 955 Black Edition with a few tweaks.
For the typical computer user, the stock Phenom II X4 955 still provides some serious level of performance, generally scoring higher than almost all the Intel Core 2 Duo processors, or about on par with the Core 2 Duo E8500 model ($190). Again, this chip can be used on AM3 or AM2/AM2+ platforms.
The Phenom II X2 555 was selected to represent the series as we feel it is by far the best value processor AMD has to offer. Its lower-end sibling, the Phenom II X2 550, is just $10 - $15 cheaper and doesn't offer the unlocked multiplier. It is also clocked down 100MHz but that is far less of an issue.
AMD Athlon II X3 435 = $75
The Athlon II X3 range features three cores just like the Phenom II X3 series, however without the L3 cache they are more affordable. This is the main difference compared to the more expensive Phenom IIs, and should have a considerable impact on performance.
Nevertheless, at $75 the Athlon II X3 435 is dirt cheap and for those on a tight budget it is an attractive offer. With a core clock of 2.9GHz it's no slouch either. This CPU was picked over the Athlon II X3 440 because it's clocked just 100MHz lower and will save users $10. That may not sound like much but it's a 12% saving for a 3% reduction in clock speed.
AMD Athlon II X2 250 = $65
If you can follow the trend above, then you know the Athlon II X2 series is the dual-core range without L3 cache. There are a number of processors in this series, with the most common models being the Athlon II X2 245, 250 and 255. For our comparison we selected the Athlon II X2 250 as it is priced at $65, making it $10 cheaper than the 255 and just $5 more than the 245.
There is 100MHz separating each of these models, a difference we do not consider substantial when we are talking about frequencies in the 3.0GHz range. Specifically, the Athlon II X2 250 works at 3.0GHz, while the 255 operates at 3.1GHz.
It is worth noting that the Athlon II X2 series features a larger L2 cache than any other Athlon II or Phenom II processor. Each core receives 1MB, whereas all other Athlon II and Phenom II chips do with 512KB of L2 cache per core.
AMD Sempron 140 = $33
Finally for those scraping the bottom of the barrel we have a $33 processor known as the Sempron 140. This Phenom II-based processor does away with the L3 cache and works with a single core bolstered by a 1MB L2 cache. The lone core is clocked at 2.7GHz and has a thermal design power of 45 watts.
The Sempron 140 is the only processor in the series, though a Sempron 145 processor running at 2.8GHz is rumored for release later this year. This might be the least exciting processor of the bunch but at half the price of the Athlon II X2 250 it is also by far the most affordable. When compared to the Athlon II X2 250, the Sempron 140 is almost the same processor minus a core and 300MHz in clock frequency.