I placed an order yesterday for a 50Mhz full-size TTL crystal oscillator. I plan to use it to “clock chip” my old Macintosh IIsi. (For more information on clock chipping, visit this excellent site.) Anyway, the IIsi has a Motorola 68030 CPU running at 20Mhz, half the speed of the 40Mhz crystal that drives it. I plan to replace this 40Mhz crystal with the 50Mhz part I ordered from Mouser Electronics. This form of overclocking should gain me nearly a 25% boost in performance, driving my CPU speed from 20Mhz to 25Mhz. Anyway, I’m really looking forward to performing this surgery. The IIsi’s logic board is removed and my soldering iron ready!