That FSB is "quad-pumped" so it's raw clock rate is 200 MHz (800 / 4).
DDR is "double data rate" so the raw clock rate of your DRAM is 400 MHz.
FSB : DRAM = 1 : 2 (i.e. 200 : 400)
Download and run CPU-Z for confirmation:
CPU-Z reports "Bus Speed" and "Rated FSB".
Yours should be a Bus Speed = 200 MHz and Rated FSB = 800 MHz
(at stock settings).
I hope this helps.
MRFS