All SDRAM is capable of being clocked downward from it's rated speed. If you choose to run this memory on your current board, it will simply run cooler and allow better overclocking, these are not bad things!
The 8SG667 and 8SG800 are single channel boards that support your memory at full speed. The 8SQ800 and SINXP1394 support your memory in dual channel mode.
<font color=blue>Watts mean squat if you don't have quality!</font color=blue>