Whelp, I've decided to follow @GeorgeStorm 's advice and stick to 64GB. Trying to achieve stability at 4800MHz was basically impossible, let alone any higher. In fact, the Corsair RAM (that I've returned today) was better performing in this regard, being able to hold its latency values from the 6600MHz profile. I'm currently stress testing one set of RAM with Prime95. Unfortunately, its 6400MHz CL32 profile had one core fail after 50 minutes (even when trying the alternative EXPO profile, which actually failed pretty much immediately); the 6000MHz CL30 profile has lasted an hour. Going to swap out the other set and see how that performs.
The other set of RAM passed 2 hours or Prime95 testing. So, on to the next thing... Whilst waiting for the stability test to do some decent time, I read a bit more of the Techpowerup article about RAM speed and latency performance I linked earlier. In some cases, it was better to have lower latencies than higher frequencies. Curious, I ran Cinebench (R23.2) a few times with the two profiles. Here are the results: 6400MHz 32-39-39-84 23513 mean 6000MHz 30-36-36-77 23565 mean Common factors Standard deviation (sample) of 11 for both. At least 5 tests done. Test done until result stopped increasing. Highest three results used. Since the Cinebench performance correlates with gaming performance (admittedly making a fraction of a percent difference), I'm going to use the 6000 MHz profile. Also, I must update the OP with details later.