Old server hardware can be very cheap, although it's not necessarily the best value. Typically it only makes sense if 1) you need a lot of memory, 2) you don't

Old server hardware can be very cheap, although it's not necessarily the best value. Typically it only makes sense if 1) you need a lot of memory, 2) you don't mind a slightly higher power bill and 3) you don't care about single core performance. I've used a 12-core Haswell Xeon as a desktop for about five years (got it used for around $500, plus $200 for a brand new LGA 2011 v3 motherboard). At the time it was twice as fast as a high-end desktop 4-core CPU. It's still reasonably competitive on multithreaded workloads versus a recent 6 core desktop CPU, but fares poorly on single-threaded tasks. DDR4 was a bit expensive back then, but quad channel memory helps in that you can buy lower density DIMMs. Today, even DDR4 ECC RDIMM server pulls are dirt cheap. I picked up 4x16GB DDR4-2400 RDIMMs for just $90 last year. I'll probably replace it with a 5900X soon, but it's served well over the past five years. Certainly much better than a i7-4770K box from the same time.