Out of the range of sub-$100 processors tested we often found it was AMD's offerings delivering the best overall performance. Take the $100 price target for example, here we have the AMD Athlon II X4 630, Phenom II X2 555, Intel Pentium E6600 and Pentium G6950 processors.
Those seeking a quad-core processor -- and we suspect many of you are -- the Athlon II X4 630 is a godsend. If we were to break the $100 budget, its higher end Athlon II X4 635 sibling is roughly $5 more and carries a 100MHz speed bump which doesn't pose a meaningful difference.
An obvious take in from our tests is that any software program capable of utilizing four cores will place the Athlon II X4 630 at a significant advantage. Applications such as HandBrake and TMPGEnc 4.0 XPress strongly favored the Athlon II X4 630, making it the best choice for encoding. It also proved to be a respectable gaming solution despite its missing L3 cache. Keep in mind we were testing with a rather high-end graphics card, the ATI Radeon HD 5850, so GPU bottlenecking should not have been an issue here.
The Phenom II X2 555 is also a great choice at $100 if you want to unlock the two dormant cores. We were able to do this with our sample and obtained Phenom II X4 955 performance with the click of a button. Of course this is not guaranteed, but given its price we feel the risk is well worth the reward, especially given the high rate of success.
Intel's Pentium E6600 put up a decent fight, but it simply cannot hold a candle to AMD's superior offerings in this price range. Furthermore this processor is based on the LGA775 platform, which is now at the end of its life. The only reason we included this and other LGA775 parts is because that is what Intel continues to peddle at under $100.
The Pentium G6950 was the only redeeming processor from Intel in this price range. The LGA1156 platform is very young, reasonably priced and should see many new processors over the next 12 months. The gaming performance of the G6950 was strong, while the encoding performance was average, often quite a bit slower than the Phenom II X2 555. It did rather well in our application testing, and is a far better overclocker than any AMD processor featured in this article. The G6950 is also a very efficient processor, consuming little power when idle and under load.
Moving down the list we have the AMD Athlon II X3 435 ($75), Athlon II X2 250 ($65) and Intel Pentium E5400 ($70) processors. Given the latter is an LGA775 processor, most can write that off without much thought. Not just because the supporting platform is on its way out, but also because in terms of performance it was quite poor.
So then again the comparison comes down to AMD's Athlon II X2 250 or Athlon II X3 435. For a mere $10 extra, the X3 435 was consistently faster given it features the same architecture with an extra core and a 100MHz clock speed advantage.
At the bottom of the barrel we have the Intel Celeron E3300 and AMD Sempron 140. Priced at $52 and $33, respectively, both processors lagged behind on tasks such as file compression, graphics editing and gaming. Surprisingly, the Celeron E3300 was not too bad when testing encoding performance, but the Sempron 140 takes so long it would be quicker to save up for the Athlon II X4 630. Overall, we would avoid either processors at all costs, as they are designed exclusively for light work tasks such as word processing and e-mail.
In a nutshell, if you are looking to spend no more than $100 on a CPU then we definitely recommend the Athlon II X4 630. The Phenom II X2 555 is very tempting as well if core unlocking is on the cards. Then at around $70 we recommend the Athlon II X3 435 exclusively, as we feel it is hands down the best offering at this price point. In fact, we recommend this as the cheapest processor you can purchase for those looking to get the most bang out of their buck.
Last minute update: As we were wrapping up this article, AMD announced half a dozen new processors in the budget and value price ranges. On its majority the announcements consist of slightly higher clocked models in the Athlon II family for about the same prices as previous flagships. We don't believe this announcement will affect our findings or recommendations above, and if anything, pricing for the AMD processors could correct downwards in the $5 to $10 range, reinforcing our recommended buys.