Hmmmmmmm...
Received the Centon DDR yesterday, Spectek chips 7.5ns CL2.5
Popped it into a board, it only showed up as 128MB. Tried all the usual troubleshooting, no dice.
When to local OD today to return or exchange it, decided to try exchanging it for another seemingly (visually) identical Centon module (was all they had), just for the heck of it. Replacement module works fine, still rated/SPD programmed as CL2.5 but 5 hours testing shows stable CL2 @ 133MHz. No further testing done at higher MHz.