The problem:
There occur problems with many games when we use AMD Athlon 64 X2 Dual Core. Among those issues are hitching of the graphics, the speed of the game dropping or changing suddenly. These problems are usually caused by missing drivers for AMD Athlon 64 X2 Dual Core processors.

Solution:
Install the latest versions of these programs:
1. AMD Dual-Core Optimizer
2. AMD Athlon 64 X2 Dual Core Driver
The drivers for AMD Athlon 64 X2 Dual Core can be found on the AMD company's website.

These drivers are meant EXCLUSIVELY for AMD Athlon 64 X2 Dual Core processors and installing them on a computer with a different processor can cause damage to the system.
link