GREAT NEWS!
I've got it running at 300MHz and it's much more reliable than at lower speeds. I now have 2 chips doing 600 MH/s total with fairly long periods with zero HW errors.
I tried several capacitor values for result capture and the 30pF works well up to about 360MHz. At 380MHz it's lost sync. I tried a brief run at 360 MHz and it worked ok. I need to get a fan working before I run extended tests at higher clocks.
I'm following, but not super closely.. Doing Result capture like this, are you using good capacitors (2, 5, at most 10%) or are you using standard +80%/-20% caps? If you're having to tinker with values that much, then variance between the parts that people buy is going to be a real issue..
Add-On: I just looked.. the 30pF is a 5% part, so that's a plus.. I would still suggest buying a few of the same part number from different vendors (to guarantee you get samples from different manufacturing lots) and make sure the variance doesn't cause issues..
Enigma