Hmm. Im not a fan of the 7900x. It has two CCUs like the 7950x, but only 6 cores per. It ends up being pretty awkward in practice on my 7950x3d. I’d recommend going all in on a 7950x, or do a 7800x3d. Im not educated on if the extra cache benefits LLM, but it’s a fantastic value for the money.
Information moving between CCU’s is troublesome with certain workloads. I’m not referring to the lopsided cache, but rather the limitations of what is basically two CPUs merged together and the complications that adds to their shared I/O.
I don’t recommend the 7900x because it is a failed 7950x. I recommend the 7800x3D and the 7950X as long as the prices are within stretching for. The 7950x3D fits a very niche role as well.