How to test workstation performances ?

Hi,
I’ve found a really really interesting second-hand workstation for sale. I’ve planned to test it and maybe buy it this Friday but I’m a total noob at system benchmark…
The computer is a HP Workstation Z620, and the specs:
Intel Xeon E5-2620 (2,0 GHz, 15 MB cache, 6 cores)
Chipset Intel C602
32 GB RAM DDR3 ECC
Samsung 840 Pro 256GB
Nvidia Quadro K5000

How could I test the global stability ?
Should I try to run a really heavy TD patch during hours ?
Thanks for your help !