Well I have one T-bird @1450 not doing anything...
At the peak I can have an additional 6x PIII-667, 4x Athlon 900, 9x Duron 600, 9x Athlon 700, 5x Celly 566, 21x PIII-866; also have ~20 Celly 466s that I haven't bothered to tap yet.
Of those I can only be sure that the Durons, Celly 566s, and 3 of the Athy 900s are actually running; & from my recent totals it doesn't look like much else at the moment is.