The PC is pretty powerful with 8 cores, 40Gb RAM and SSD throughout. The blockchain is on its own disk.
I haven't used Windows
ever for Bitcoin Core, but with those specs a computer shouldn't freeze from verifying a few blocks. I can only imagine disk-IO being a limitation, but with that much RAM that shouldn't be a problem. If your OS can't properly multitask, changing priority isn't going to help.
I did this in Windows and it initially stuck out everything on the side and causing chaos online.
Of it gradually improve with time.