I set up a VM for running folding@home to help with research. I had trouble finding information on how much CPU and RAM to assign, so I gave it 4 CPUs and 8GB RAM. It turns out it’s really only using one CPU — apparently the COVID problem doesn’t parallelize easily — and a bit less than 3GB RAM. So a Linux VM with 1CPU and 3GB RAM is probably effective, and if you have a system that’s on anyway and has unused CPU it’s probably worth spinning up a Linux VM and joining the party.
The blocks can take a while to crunch. I’m using CPU only. If you have a desktop and can let it use GPU I think it goes a lot faster and can probably handle blocks overnight. For me, on the processor I have already running 24/7, it’s going to take more than a day for a single block of work. But it’s already running, so might as well let it do something useful.