Need help,I need to choose between ryzen or xeon

Hi, first time here.

I need to work with Intel e810 NICs (I need XDP — eXpress Data Path — hardware offload support and DDP — Dynamic Device Personalization). I think the e810 25G is a good price/performance, but I may change it later, and other components must be compatible with it.

These PCs will be used headless — ZTP for the first configuration, then SSH for all stuff.
I’ll need two systems, one for pktgen. I need to run benchmarks for research purposes.Since pktgen is not easier than receiving high pps,I’m thinking buying the same.

Currently, I’m using a ThinkPad with 32 gb ddr5 and an intel ultra 5 125u and it’s more than I want for my daily work,these systems are for a university research project on XDP/DDP.
My lecturers said the hardware will be funded by the university, but if not, I won’t buy the computers myself.

I’m between two options:

  • Second-hand servers:
    Xeon E5-2680 v4 (may need two per PC because one might not handle high PPS).
    I found one locally for $20, with a 2-year warranty.
    High-capacity but old second-hand ECC RAM.
    In this option, I’m worried about unknown motherboard brands like JginYue (?).
    Even if I weren’t, I’m not sure what the university would think about funding a JginYue board.
    I live in Turkey, so buying from eBay etc. is nearly impossible due to taxes and import laws.
  • brand new ryzen:
    ryzen 7 7800x3d for the large l3
    At high gbps,accessing the ram may mess up my benchmark results,so I think it’s necessary.
    Intel CAT (Cache Allocation Technology) would be wonderful, but that hardware is pricey.
    This build would basically be a gaming PC with an e810 instead of an rtx
    The second option costs roughly 2× the first one.

What do you think, and why?

Since these systems won’t be in my home, electricity cost, space, and noise are out of scope.