Overclocking
The ASRock TRX40 Taichi showed a fair bit of headroom for overclocking. I was able to get into Windows at 4.4 GHz and 1.35 V core voltage, and I used this overclock for my power consumption tests. However, under heavy AVX workloads, I found much less room to work with. I ultimately ran my thermal torture test at just 4.0 GHz (about a 200 MHz overclock). This was partly for stability and partly to avoid overloading my CPU cooler and throttling the CPU.
The postcode display on the ASRock TRX40 Taichi is well placed for easy problem diagnosis, on the bottom of the board, below the M.2 heatsink.
For memory overclocking, I was able to test stable at 4000 MHz on the final BIOS ASRock's QA team provided me. 4000 MHz is a great result at 16-16-16-36 and 1.35 V, though there is frankly little point to pushing past the already excellent XMP 3600 MHz of my Trident Z Neo kit.
Memory QVL lists are incredibly important. As a reviewer I have to use a standardized memory kit, and I can't always fit that into a board's QVL. I am also able to interact directly with a vendor to help troubleshoot when problems arise. While even buying off the QVL list is no guarantee of stability, as the CPU memory controller still plays a large role in memory stability, it is still best practice and one more variable a buyer can control.