Older Xeon systems (v3, v4) give you oodles of cores, main memory channels, and PCIe lanes. Single-threaded performance isn’t great, but for multi-threaded workloads they’re great value for the money and power.
Compare those threadripper systems to R730, T7910, and T7810, with E5-2680 and E5-2690 processors, and see which makes sense to you and your use-case.
Quite welcome :-)
A few places:
Intel ARK for full CPU specs
CPUBenchmark for estimating perf and perf/watt
eBay for figuring out modern prices – E5-2660v3 can be had for about $15, E5-2698v4 for about $110
Also eBay for figuring out what servers are available for cheap with a particular socket interface
This very subreddit of course :-) y’all rock