So, my budget is 3KGBP, my use case is i do 3d modelling work (have done for 25years now), and would like a better machine that i can do (light) GPU render tests on. It will likely also do short (few days) runs of CPU rendering too.
Naturally, no amount of horsepower or RAM is ever really enough for 3D rendering, but this is the best config i could come up with within my budget.
As far as gaming goes, since i only turned to that recently (more and more as i get older it looks like), i only own 3 games: KSP2, Cities Skylines II, and X4 Foundations (so far), but its not a primary concern for this machine, just a nice-to-have.
Now i know, i am about to be told i sould go with AMD, perhaps the 7900 X3D?
Main reason im going with intel is i sometimes use older windows software, which i have had issues with AMD (mostly very niche 3DSMax Plugin stuff), but that was some time ago now, but i am very fearful of that.
I wont be overclocking it, as i need it to be stable, and will likely be doubling that 96GB of RAM in a couple of months, and no, it still wont be enough :(
I would be greatful for any advice, especially on the AMD side of things.
When AMD launched Ryzen they deliberately offered way more I/O bandwidth than Intel.
The first generation Ryzen CPU's used RAM frequency that could cause performance issues if you used low frequency RAM. That got fixed in the 3000 series.
There are a small number of Ryzen CPU's which end with "3D," it means they had 3D Cache memory and its supposed to add rediculous performance in certain situations. Phoronix runs tons of benchmarks on CPU and GPU.
The only Intel instructions AMD haven't implemented is AVX-512 and AVX-10. No one uses AVX-512 as Intel CPU's get so hot they performance throttle so much its faster to not use the extension. AVX-10 is something new Intel released this year to get around that.
AMD does support AVX2 which a lot of Audio/Video products do use.
Your AVX statements are out of date. Nowadays AMD supports AVX-512 but Intel removed support from the consumer line (only workstation and enterprise products support it for the last 2+ generations)