I have a Slot 1 SMP motherboard, and I'm getting two CPUs that have 512K
cache each. How much RAM would be cacheable? The board supports up to 2GB
of RAM, but installing more than is cacheable might not be such a good
idea. If it matters, the chipset is Intel 440GX.
Cacheable memory was determined by the CPU for Slot 1 systems, and
yes, you are correct that it is definitely NOT a good thing to put
more memory in than can be cached. Beyond the cacheable limit Slot 1
CPUs tended to disable both L2 *and* L1 cache, which basically turned
the system into a 386.
Getting back to the original question though, it all depends on just
which Slot 1 chip you select. The original "Klamath" PII chips (280nm
production process), sold at 233MHz through to 300MHz, could only
cache 512MB of memory, so you'll almost certainly want to avoid these.
The latter "Deschuttes" PII chips (250nm), sold at 266MHz through to
450MHz, and all PIII chips could cache up to 4GB of memory. Same goes
for the "Mendocino" Celeron chips, though the original "Covington"
Celerons had no L2 cache at all.
Long story short, if you buy any chip at 333MHz or faster, you're
safe. If you go for a 233-300MHz chip though you'll want to make sure
that you get the right type. Intel's sSpec numbers are the best way
to tell here. Of course, these days there's really no good reason to
get a 300MHz or slower processor!
