I'll try to clear this up for ya... (read the bold print for the short answer
)
ok first off, don't confuse "effective" speeds with actual speeds...
-Intel's FSB is "quad-pumped" so it's effective FSB speed = 4 x [actual]. for example, a C2D with a FSB of 1333MT/s has an actual speed of 333MHz.
-DDR2 is "double-pumped" so it's effective speed = 2 x [actual]. for example, a DDR2-1066 effective speed is 1066MT/s, but it's actual speed is 533MHz. if the C2D's FSB was 1333MT/s then it only needs a DDR2-667 to match it's speed 1:1.
as for the C2D FSB speeds, only the E6550, E6750, and the E6850 have a FSB of 1333MT/s (333MHz), all other C2D models have a FSB of 1066MT/s (266MHz) or 800MT/s (200MHz)
as for the RAM speeds,
the corsair dominator RAM sticks you're referring to have a default "SPD" spec of 800MT/s (400MHz), but are guaranteed to operate at 1066MT/s (533MHz) when "EPP" is enabled in the BIOS. it's basically a DDR2-1066 RAM stick cleverly marketed as an "guaranteed overclockable DDR2-800 RAM stick". the only difference being that the faster EPP settings are actually programmed into the SPD.
IMO, EPP is useless. it's just marketing aimed towards people who want to overclock but are unwilling to learn how
... the EPP enabled RAM sticks cost more, so the manufacturer makes more money off of people who want to "overclock automatically". my advice would be to forget about the EPP RAM and read a few basic overclocking guides, and overclock manually instead. if you buy RAM that is fast enough to begin with then you can overclock the CPU without having to overclock the RAM at all, for example instead of buying DDR2-800-EPP just buy DDR2-1066 instead
hope that wasn't too confusing :wave:
