I have been doing research about this problem after I was confronted with it when I ran the WEI (Windows Experience Index) or when watching Youtube videos. After a little digging around the web, I have a strong feeling that the CPU is not getting enough power. I have tried all the setting in the BIOS, like increasing and decreasing the HT, the CPU volts, RAM volts, Timings, underclocking the CPU, but all to no avail. I am honestly stuck.
This is the system:
CPU: AMD Athlon II X2 245 @ 2.9GHz
MOBO: Biostar A880G+ (Revision 6.1)
GPU: Biostar HD 5670
PSU: Cooler Master Elite 460 Watts
HDD: Western Digital 500 GB