In addition to JMH's excellent suggestions, getting the basic health of your system is the priority, there is a known issue with AMD integrated memory controllers running with a RAM frequency above 1333MHz. VERY IMPORTANT INFORMATION REGARDING AMD AM3 CPU's and RAM SPEEDS Q&A for the topic VERY IMPORTANT INFORMATION REGARDING AMD AM3 CPU's & RAM....
This affects all motherboards, it is due to the AMD CPU integrated memory controller.
In reference to JMH's above points.
Use Core Temp
to test the '* Make sure that you are not over heating', check the CPU temps when at idle, under load and/or testing.
After you run memtest86+ and post the results, D/L CPUZ
and post a snip of the CPU, Mainboard, Memory, and SPD tabs.
For posting the information , enter 'Snipping tool' in the Start button > Search box, hit enter. Select the area you want to post and save to a convenient place. Post a snip of the tabs, it is much easier for everyone to see the information. How to Post a Screenshot in Seven Forums