With your current memory knowledge, I advise not to buy or change any of your memory settings. Not trying to be a dick. I just don't want you to bork up your computer. I will give you homework.
Learn and demonstrate your knowledge of these skills:
1) CLEAR CMOS. Most important, otherwise a bad RAM setting could keep your computer from POSTing.
2) Adjust DIMM voltage and CPU-NB voltage.
3) Understand the relationship between CPU-NB speed and RAM speed on the AM3+ platform.
4) Adjust CPU-NB clock and memory clock. Manually tune ALL memory timings.
5) Benchmark to demonstrate improved performance of tuning your memory controller and RAM.
6) Stability Test your settings.
Complete those tasks in order and come back to discuss your progress.