Quick update for anyone wondering the same as I was. I've installed the Corsair Dominator Platinum 32GB 2400MHz kit on the Crosshair V Formula-Z and it works with no issues.
I set the NorthBridge to 2400MHz in BIOS and that's all really.
The AMD FX 9590 now runs a fair bit hotter despite the Corsair H110i GT liquid cooler. I always have a bit of trouble discerning true temperatures but pretty sure it's idling now, having done very little, under 30 degrees in quiet mode, but during spells of GTAV and rendering sessions I've seen it above 40 degrees.
I'm not so clued in on overclocking and benchmarking, but I did do my own pseudo-scientific tests using a video I had ready to render to see what realworld benefits various configurations yielded, and how stable it was under load.
There was actually one bluescreen, very rare on this machine so far, while rendering the video a second time, directly after completing it first time round using the 32GB @ 2400MHz configuration. Since then I've had no issues, including while gaming (GTAV, Cities: Skylines), recording said games and editing/rendering. So willing to give that a pass as a Sony Movie Studio Platinum anomoly.
In short: The Crosshair V Formula-z can run 32GB of RAM at 2400MHz, but seems to generate a lot of heat doing so.
Thanks for your input and helping me decide whether to give it a try or not. I will update this if any more information comes to light, and please, if you spot anything I've done incorrectly, do point it out.
For those with more than a passing interest; below are some details of the "testing" I did.
The results are far from comprehensive, but give some small indication of performance gained.
Parameters and Method
The test used a 17GB, 8 minute 46 second, 1080@30fps recording of GTAV. I used all my usual amature editing effects. Transitions, fades, overlays, overlay animations and audio channel volume envelope shaping, and produced an 8 minute 36 seconds, 861MB mp4.
I tested 3 configurations, and rendered the video 3 times on each. First I would cold start the computer switch cooling to performance mode, and render the file. Upon completion, I would immedietly render the file a second time. Then restart the computer and render a third time.
Noting time to completion I would compare the average and best times of each configuration. Cold boot then render was always quickest.
Memory Configurations
Common: AMD FX 9590 4.7GHz with 5GHz boost stock, ASUS Crosshair V Formula Z, GALAX Hall of Fame GTX980, 1000w PSU. Sony Movie Studio Platinum, rendering on the CPU (not GPU)
Test 1: 8GB Kingston Hyper X Beast @ 1600MHz
Test 2: 16GB Corsair Dominator Platinum @ 2400MHz
Test 3: 32GB Corsair Dominator Platinum @ 2400MHz
Results
Test 1: 8GB @ 1600MHz
Best time to render = 1125seconds
Average time to render = 1130seconds
Test 2: 16GB @ 2400Mhz
Best time to render = 977seconds
Average time to render = 989seconds
Test 3: 32GB @ 2400Mhz
Best time to render = 971seconds
Average time to render = 978seconds
As you can see, there is a noticable 12.5%-13.26% reduction moving up to 16GB @ 2400Mhz over 8GB @ 1600MHz
But surprisingly, to me at least, increasing to 32GB yielded just a scant, but consistent, 1% gain over the 16GB config.
Perhaps using a much larger file (often my recordings exceed 150GB, sometimes as much as 250GB) would demonstrate the advantages of 32GB but I really have no idea. The gain in moving up from 8GB @1600MHz to 16GB @2400MHz is a tangible one and seems a good proposition considering the other areas an improvement such as this will certainly benefit, but 32Gb really hasn't given any noticable improvements and does not seem like a good option if one were to consider "value for money" as an important factor.
I was very curious to see first hand how this would play out and I think the thirst for that knowledge really was the reason I opted for the 32GB set. While all this took a while, I did find it quite fun... such a nerd.
Hope someone finds this post informative or interesting, I might attach my data below if I can see a way to do so for extra nerdage.