From the "SQL Server 2017 Administration Inside Out" book:
Windows uses the page file for virtual memory for all applications, including SQL Server, when available memory is not sufficient for the current working set. It does this by offloading (paging out) segments of RAM to the drive. Because storage is slower than memory, data that has been paged out is also slower when working from the system page file.
The page file also serves role of capturing a system memory dump for crash forensic analysis, a factor that dictates its size on modern operating systems with large amounts of memory.
This is why the general recommendation for the system page file is that is should be at least the same size as the server's amount of physical memory.
Another recommendation is that the page file should be set to System Managed... However, in systems with large amounts of memory, this can result in a very large page file, so be aware of that if the page file is located on your operating system (OS) volume. This also why the page file is often moved to its own volume, away from the OS volume
Best is avoid SQL server using page file (virtual memory) at all as it dramatically reduces performance. Buy/install enough RAM memory to cover your SQL Server needs so it does not need to use page file at all
To find out how much RAM memory your SQL Server actually uses, you can do it by monitoring Performance Counters:
Target Server Memory
Total Server Memory
Database Cache Memory
Stolen Server Memory
Log Pool Memory
SQL Cache Memory
Reserved Server Memory
Granted Workspace Memory
Looking at those and figuring out how much your SQL Server consumes over time, will give you idea if you need/install or allocate more RAM memory to the server or 512 GB is enough for you (or alternatively, optimize queries, indexing, table design, to make it use less RAM)
Hint: look for
Total Server Memory - this is total how much your SQL Server consumes. Roughly
Total Server Memory =
Database Cache Memory +
Stolen Server Memory +