Re: AMD overdrive vs MSI afterburner
AMD OverDrive is for overclocking your cpu and memory. MSI AfterBurner is for overclocking your video card.
You should overclock your cpu through the bios, but the OverDrive utility could be useful for "pre-testing" various settings.
The Fusion Utility could also be useful, but if you don't know what your actually adjusting then you probably shouldn't. I don't have an AMD system to actually see what it does, but it sounds like a tool for the advanced user.