SAV for NAS runs fine under a VM.
It can be deployed on 64-bit OS but it runs in 32-bit emulated mode and therefore can't really address more than 2-4GB of ram.
A single SAV for NAS box can scan files at the rate of 18-20MB/s so performance will depend on your NAS and file scanning policies.
Are you going to scan all files?
Are you going to scan just executables?
User profiles are notorious for hampering performance and need to be treated with care if the NAS is full of them.