Originally Posted by alexh
I work with these things day in day out and the 100+MHz speed ratings they give in datasheets are marketing bullcrap. They are like the maximum frequency for a one flop or something. Once there is a semi complicated design in with a fair amount of routing and clocks and the speed drops off fast. I'm not saying it isn't possible because I've not tried that device but I would have to see it to believe it. I don't think you're going to get anything near the complexity of a 68060 in a $30 Spartan 6 running at 100MHz. Dream on.
I've got a £2k Virtex 6, fastest speed grade, largest capacity device here and it struggles to do my designs at 150MHz.
I was checking the licensed soft cores for Spartan 6 when estimating the clock speed where MicroBlaze was tested around 120MHz. This was a mistake I gather from your experience, probably due to the gate count a 68060 would require. So how about 50Mhz then? It would still make an interesting product.