There has been the Achronix Speedster 22i HP(high performance), which was said to reach 1Ghz, produced by Intel at 22nm. That is now out of production, it seems.

I am angry for not having bought at least the 22i HD(high density) development kit, when it was available for 999USD for a time. But the software license was only valid for a year, so no-go.

They now offer embeddable FPGA IP cores targetting 750Mhz on TSMCs 7,12&16nm process.

And 'normal' FPGAs, the Speedster 7t, manufactured by TSMC at 7nm, also 750Mhz fmax.

All rather expensive and out of reach for the hobbyist :-(

> Although FPGAs certainly can't touch gigahertz+ range yet. Even 500 MHz is... challenging.

It's a relative difference though, that depends on what material you're building the circuit in. If you can build an FPGA to run at 1/10th the speed of a 6502, then with a sufficiently expensive process you get a tradeoff between a very weak 80GHz processor and a customizable 8GHz circuit.