You're missing quite a bit. An unoptimized client _will_ run that slowly.
Just like Alphas shouldn't be running slower than Pentiums, Power Mac
clients should be running faster than they currently are.
The MacOS doesn't pre-emptively multitask, but if the client is written
properly (takes a little work, but there are plenty of us willing to do
it), it will run fine in the background and give time when necessary.
My 150 MHz PPC 604 does about 500kkeys/sec under Linux, which is just about
the best (relatively speaking) I've seen for a non-Intel client.
Vijay