Here is the problem: most of these stats are not what they pretend to be (unless exact circuit / spec is published). Look at low level details of building say avalanche noise source: http://holdenc.altervista.org/avalanche/ - bandwidth is mostly bound by voltage/frequency/sampling resolution - how often you can trigger entropy event and how many of them in parallel? True result for one AN circuit: 2000 bits/sec.

What a lot of these vendors do is have some physical phenomena on the chip that feeds hardware "whitener" (endless hashing) that responds without blocking to all requests. That's practically hardware version of “/dev/urandom" that is bound only by chip IO - but its completely disconnected from bandwidth of actual “true” entropy phenomena underneath. of course it is still good CSRNG, but its not “true” source. btw nice exception: TrueRNG team are pretty honest providing direct schema - hence the real entropy speed of 40kb/sec.

In short every single entry on that list should be independent inspected down to specs and schema of whitener. If they are not publishing chip spec with exact details I highly highly doubt the bandwidth of “true” entropy events are really approaching GBps - this is the speed of whitener, not of actual generator.