It doesn't boost the system all that much.  On the '040, you don't win much
from a cache.  Further, with something like the warpengine, you just get
fast RAM, and you don't have any wait states anyway.  Cache wouldn't speed
it up at all, in this case.

It's more of a concern in the price-conscious PC world, where people tend
to use slow memory, because it's cheaper, and then need a cache to make it
acceptably fast.

-s