How to enable more than 4 GB in SQL Server X86 under Windows X64

AndreaTaroni86 asked:

I have read here that I can use more than 4 GB in X86 SQL Server Systems and X86 Windows servers via /PAE option, but my scenario is different.
I have a 32 bit SQL Server std in a Windows 2019 X64 std and I am going to upgrade to Sql Server X64 version.
But I’m wondering, can I still enable somehow my sql server to use more than 4 GB even if it’s X86?
I’m asking it because with /PAE option in X86 server I can extend SQL Server memory (If I understand correctly), so maybe I can do something similar in X64 Windows server enviroment.

My answer:

PAE is a processor extension providing the CPU the ability to access 36 bits of physical RAM (236, or 64 GB). It lets a 32-bit operating system use more than 4 GB of RAM, up to 64 GB total, but because the address space is still 32 bits, any single process itself can use no more than 4 GB, and in practice somewhere around 3 GB (the remainder of the address space being used by various system hardware).

If a 32-bit program is run on a 64-bit OS, then the 3 GB barrier goes away and it can access (nearly) all of the 4 GB, because the system hardware no longer needs to be in the process’s address space. But there is no way to break the laws of physics or math, so 32-bit will always max at 232, or 4 GB.

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