HP Z620 system - adequate for hashcat
I'm on a limited budget but I willing to stretch for this system:
HP Z620 Workstation
E5-2660 2.2GHz 8-Cores (unknown version)
Quadro 4000 2TB HDD
Windows 10 Pro
All in price about $550.

The PCI specs are:
2 PCI Express Gen3 x16; 1 PCI Express Gen3 x8, 1 PCI Express Gen2 x8 mechanical/x4 electrical; 1 PCI Express Gen2 x4 mechanical/x1 electrical; 1 Legacy PC

I know the Quadro 4000 isn't great for cracking but I'm just getting into this after doing some on my laptop.

I like Xeon and having a large case with lots of bays for other drives (long story).  Should I buy it or is there just a much better choice in server grade workstations?
You can get Z820s for that. Dual socket too: Higher power supply, 2 CPUs, can hold 3 double wide blower GPUs (I used GTX 1070s) all day long. Check newegg.com - prices were lower before the epidemic.