Some BIOS makers will show the real speed of the RAM (400MHz) and some will show the DDR2-xxx speed. In your case, I think they are showing the DDR2 speed, in which case you want it to be at 800MHz.
The other settings are there in case you overclock. Technically, the speeds they list are not really speeds, but math equations. The 400mhz is "run at half the speed (.5 x FSB)" and the 800MHz is "run full speed (1 x FSB). Since you say you're a newb, this is called a memory divider, in case you want to look it up.
Thanks mate. On CPUZ-ID it says that my DRAM frequency is 371.4mhz, which sounds about right. The timing are at 5-5-5-18 at the moment, do you think lowering them to 4-4-4-12 would make much difference?
it will go faster at a tighter timing but it might heat the memory up or cause some blue screen of death, BSOD, try 4-5-5-16-26 at voltage 2.0 or 2.1 and can u set your CPU frequency at (200.5) beside (200.0) ? play around with it and see if what best for u and the clock for stability