OK, i know what is happening, i was flicking through my
mobo manual the other day since i was bored, and dual channel will only work with either 2 or 4 memory modules, because if you had 3 the 3rd would need to be split between channels, if the extra speed matters then remove ther 3rd module if you prefer the extra memory, keep it in, and to change from t2 to t1 you need to access the bios
as for the slowness, you're probably better off changing the memory timings than changing the FSB, i can get mine down to 3-3-3-9 with a little extra volts, 2.1v from 1.8, and the best thing about it is its cheap kingston valueram, it works well but is easy to replace, i can also get it to run at 4-4-4-12 at 800mhz, with a little extra volts (on each of these dropping it by 2 levels from stock)