FYI, Tandy 1000s ran at like 4-8MHz. The standard 8088 was 4.77MHz
I have a Tandy 2500 with a 386/20MHz. I have a few old macs running at 8MHz and an old 8088 I'm tinkering with(I beleive it's 8Mhz)
Finally, I still have an Apple //e ;P Bet THAT!
Oh, and another FYI, the processor in a calc such as teh TI-89 is actually very similar to the original Macintosh ;P 68k. Though, it runs at 10MHz(HW2 is 12, I donno HW3...)