Mushkin uses 7.5ns chips on there PC-133 Rev.3 thats rated 150mhz CAS2
i have had mine (2 128 megs sticks of it) 100% stable @ 154mhz fsb CAS2 + Turbo settings
this stuff is FAST and STABLE
nice ram
infineon 6ns ram is good to but mushkin makes better ram moduals
also the mushkin is on Black epoxy PCB that is the best PCB avalable
here are some memer bench marks for you @ 154mhz CAS2