SRAM on ZipGSX - how fast for 14MHz?

["Rodney Hester" <rod3@mindspring.com>]

Right now I'm trying to push a ZipGSX to 13.75 MHz with a 55 MHz oscillator.
I've already done the 74HC00 mod successfully.  I'm running 15ns tag RAM and
20ns data RAM, with zero stability.  It won't even finish booting.  Swapping
for a 40 MHz oscillator (the next closest I've got) cleans up everything
nicely, as does (usually) putting both 15ns SRAMs in the first (32K) banks,
flipping the jumper to 32K cache, and cranking down the speed a notch or two
with the Zip CDA while running the 55 MHz oscillator.

Should I have purchased even faster SRAM?  I can get 12ns chips, but I think
that's the fastest that is readily available.  For those who have a ZipGSX
running comfortably at 14 MHz, what speed SRAM are you using?  I'd just like
to try to gauge if I'm encountering a non-SRAM problem here.

Rodney