strange RAMs and boards

ok, i got a Tonicom pc 166 256mb 6n, and a kingmax pc150 256mb 5n(? not too sure). anyway, i can run my tonicom as high as 170f cas2, and i can run my kingmax as high as 164 cas2. however, after i got my abit ST6, it wont' let my tonicom run cas2 at 150+, but for my kingmax, it can run at 169 cas2 (have not tried higher, chip is fried ) anyway, what gives?! is boards' problem or rams'?

its most likly something in the bios or the chipset.
your ram and mobo should be just fine.

yeah, i know that, but now i cannot make any "gurantee" for either of them, for i don't know if they will work the same on every board--i want to sell them..