I have three machines. One is a Laptop running a K6-2+/450@400MHZ (old 66 bus) and 160MB ram and works great. I have a K6-III/450 with 160MB Ram desktop runs great. I also have a AMD 1700+ 1.44MHZ which rocks.
64MB of RAM is going to be the killer for you, go buy some RAM and get it up to 160MB and I assure you you will see a big difference. It will be acceptable speed.