We believe one previously announced effort at 28nm is using eASIC, so their cores are *much* bigger than they have to be. Of course their startup costs are much lower too, but it impacts the performance a lot. Look at the η-factor for other 28nm designs.
https://bitcointalk.org/index.php?topic=119668.0The η-factor thing is total nonsense for ASICs if they're thermally limited.
Also, KnC is using a standard cell design, not an eASIC 'easycopy' or whatever. eASIC is just one of the companies they work with.