@Rob:
The heatsink and fan I used made the 060 cool to the touch so it may be that 68EC chips have weaker FPU's than other versions.
Weaker FPU? 68EC chips have NO FPU. (although, some early full-equipped 68060's were labelled as 'EC'. These are mask F43G. If your chip is labelled 68EC060 with a different mask than F43G (printed in the top right corner IIRC), which I suspect it is, being labelled 60 MHz, you have no FPU.
[edit]
If a full-equipped 68060 fails the FPU quality control at Motorola, it may be relabelled as 'EC' to inform that the FPU isn't quite 100% ok.
[/edit]
@Shiva:
The cs mk1 has very fast memory access, which makes it difficult to overclock.
-Paul
