Originally Posted by BiGyLiLuPdAmIdL
Don't get the x4 635, it only has 2mb L2 cache. The i3 540 is way better than it, and even though its only dual core it has 4 total threads for multitasking. For gaming tho, I think the x2 555 will be your best bet, considering it fits in well with your budget too.
4 cores > 2 cores, cache or no cache. Hyperthreading won't help you in gaming.
L3 is nice, but not having it is not a huge deal. Heck, all CPUs worked just fine without it for years. it is a relatively new thing on the CPU scene. It allows the CPU to stay a step ahead, but the speed difference is not enough that you would be able to really tell in normal computing, and not more than a shade different in gaming.