Finally I might be able to start pushing my hardware!

Isn't it something like 2GB static memory for both 32 and 64 bit but only 2GB dynamic for 32 bit while 64 bit can have up to 8TB.

Seems reasonable. Given the age of Vista, I doubt any machine it is installed on, will have the hardware to run the game in any event. Unless the owner has upgraded...... (but, why would you do that on vista? )

Vista may have shipped with DX10, but there is a 32bit version of DX11 that will work on it. It just takes a download and install to upgrade (well, considering we are talking DX 11, it is more of a sidegrade).

DX9 could be the reason, after all, it磗 the API on which the game runs. And it磗 32bit only.

You can get DX11 for Vista, though Vista can磘 use it to its fullest potencial, because of WDDM 1.1. AFAIK DX12 wasn磘 available on Vista, because of the aforementioned WDDM, as that requires WDDM 2.

Why would they need to to that (release a 32 bit exe)?

so too sum up op's question zero CHANCE in hell 3.1gb limit will stay