|Just because you have a 6 core CPU doesn't mean your system will run faster than if you had a dual core CPU. Your system's not going to make use of all 6 cores until programs are optimized for using that many. Currenty there's very few programs that can make use 4 cores, let alone 6.|
Which CPU did you upgrade from? According to Tom's Hardware Hierarchy chart, all of the following CPUs have similar performance:
Phenom II X6 1055T
Phenom II X4 945, 940, 920, 910, 910e, 810
Phenom II X3 720 Black Edition
Athlon II X4 645, 640, 635, 630
Athlon II X3 450, 445, 440, 435
Also, the 1055T is a 125W CPU, so that means it needs a good power supply & has the potential to run hot. Have you checked your CPU temp? If your press Ctrl+Alt+Del, then click on the Performance tab, how many cores are shown? Do you have Asus PC probe installed?