You need an updated Kicktart ROM with Cosmos' Exec.library, then you can use the full 060 CPU. Otherwise you can only use a 060LC CPU.
I bought an 68060@50 MHz and I put the 040/060 adapter on my Commodore 3640 CPU board. I also doesn't have to chang the crystal.
My board als have the remove 2 wait-states mod.
CPU calculation is as fast as a Blizzard 1260@50 MHz, but the memory tests will be much slower on a 3640 with a 68060@50MHz config. Playing MP3 at Full quality with Amplifier will struggle more than a Blizzard 1260.
The problem is the speed of the Fast RAM memory.
To solve this problem you need the rare X-calibur card.
