Hardware stress-testing other than HDD drives?

Looking for a tool to stress test a NAS. Having some lock-up issues, but the only thing I can find is the built-in HDD test in the Help Desk. It’s a TS-673…and I want to test RAM, I/O, etc.

Install a VM on the NAS and run some stress test on the VM, (add as many vCPUs and RAM as you like)