sTRX4 can take one of three CPUs ranging from 24 to 64 cores. The TRX40 Aorus Xtreme that's mentioned in the thread should be the absolute top of the line even if it was launched before the 64 core monster was available. So I'd expect it to work just fine with the 3970X which is a 32 core part.

But I wonder if this is a Gigabyte issue who have a history of playing around with the power delivery and using "fake phases" (to the point where they now have to advertise their boards as having 16 "real phases"). As far as I can tell many (most?) reviewers benchmarked the board with 24 core CPUs and most likely skipped on the power intensive tests.