Thanks for for your answer, that sound like that makes sense. I've just bought and build a threadripper system and so far I'm very happy with it, it's just that I'm not sure I bought the right RAM modules. I got a decent deal on a 3200Mhz/128Gb kit and from what I gathered on the internet it would work fine. And it does, the only weird thing is that when I disable the XMP profile on the motherboard/ram it goes to 2133Mhz and the performance differences are negligible in benchmarking. So I was looking at a sim and noticed the utilization of my cpu not being 100% in all sim cases, I was wondering is this mem kit bottlenecking my CPU.
It's quite hard to find a definitive answer on this, but what you say does make a lot of sense for Houdini related performance.
If you have anymore mem/cpu insights I highly appreciate them!