X6 or X4

Solution
The X6 1100T is the best. It's a 125W processor so get a Cooler Master tx3 cooler. If the fan fails get a 4-pin 92mm case fan from Ebay.com

An fx6300 (or 8300 8-core) is a better choice though & more energy efficient
https://www.youtube.com/watch?v=82vYCdFrQv8
https://www.youtube.com/watch?v=vfr0ktiGTAI

The latest games will need an 8-core (won't work on an intel i3).
I'd want speed more than two extra cores so if overclocking is an option I'd get the X4 and overclocked the heck out of it. Otherwise the 1100T. Be aware that no matter which of these you get, some games will struggle because CPU demands have overtaken the capabilities of a lot of older CPUs.