You are correct, it changes the way Skyrim allocates ram (not the amount it allocates). It is still only a 32bit application so it can only address 4GB. Part of the OS needs to be in that address space as well, that is why we have something that is refererred to as 3.1GB limit. I am simplifying here, but on 64bit only the OS parts that are actually needed to run the game take away from the 4GB address space available to the game. Kernel, DirectX libraries, all that stuff. So for example your browser and other background processes are not taking away from this address space. Enboost frees the 4GB address space even more shifting the textures to another process (enbhost) that uses its own address space. In theory this means with all this Skyrim can use roughly 3GB for itself including world and script data and another 3GB for the (compressed) textures because of ENBoost. 6GB + ~2 GB for OS makes 8GB really a minimum amount these days :) In reality I could not make tesv.exe use much more than 2GB, yet when testing with uGrids 19. ENBoost depends on texture sizes of course, but I typically stay around 2GB for enbhost.exe as well.