Do I need to manually configure virtual memory on a modern PC with 16GB of RAM?

No, you don’t need to touch virtual memory. Windows handles it automatically, and with 16GB of RAM, the default settings are fine. Manually setting a fixed size is an old trick from low-RAM days; locking it too small can cause crashes, and making it too large wastes disk space. Unless you’re running multiple VMs or editing 8K video, leave it on auto.