Shouldn't matter on The Witcher 2, which is LAA out of the box.

LAA programs get 4GB address space on 64-bit OS and up to 3GB on 32-bit OS (with the /3GB or IncreaseUserVa 3072 trick). In theory, anyway, a game that uses artwork resources heavily can hold more of them in memory and have to go to disk less often. I am not sure, however, that TW2 ever uses memory beyond 2GB.

I do not have much knowledge about memory management in Windows OS, but I think TW2 extends the whole address range in Virtual Memory!...

When I only had 4GB and disabled the page file, Windows always reported that it's running low on memory every time I played TW2. After a few warnings the game just exited by its own.

Although the lower the settings of "Texture Memory Size" was the more the game ran before getting a warning, but ultimately it even ran out of RAM when set to small.

With a pagefile this wasn't an issue, but screw the pagefile, I bought 16GB.