The actual slowest computer ive used (clock speed wise) was probably 620Mhz
But the "slowest" running computer i used was a 2.6Ghz Dell we had in secondary school (high school)
This thing ran SLOWER than my 620MHz cause there was SO much crap on them scanning like mad... >_<
But my 620 was pretty damn decent anyway, was especially good for numbers.
But it died... *moments silence*
Now i have a 2.86GHz (variable at that, smartchip

) Toshiba.
Runs nicely, still miss the 620 though
And the hard drive that ive still not taken in to recover anything i can from it when it broke