But 60MHz doesn't surprise me.
The '060 did it, so why not?
Intel design a chip and then speed bin it to get the fastest parts and when yield increases they apply speed limits to parts. Motorola design a chip for a specific speed and then sell it with that rating. The only exception I can remember is the 68000P12 being rated at 16mhz (the P8 and P10 were rated at 8mhz and 10mhz).
The why and why not a chip can run at a speed is complex, the design tools generally leave a large margin but all the interactions can introduce problems.
The SEC was aimed at the low powered embedded market and because it's fully static you can stop the clock, the non static versions need to be clocked to refresh the internal state (similar to dram refreshing). You might find that running at ~60mhz introduces too many errors, which you probably don't care about when running amiga software but in a pace maker it might be more of an issue.
