I'm not the most intimate with computer workings, but isn't the main issue with DF processing speed, not really the memory size? Does this change have any worthwhile effect on speed?
I believe many people are having trouble with worldgen crashing on large worlds or particularly long histories as they RAM usage of the program is exceeding 2GB. This is the default upper limit for a normal windows program I think, hence the crash. The file in the OP flags the EXE so windows "knows"(?) the program can use 4GB of RAM (3GB in XP) and won't crash when the normal upper limit of 2GB is reached. I'm pretty certain it should have practically no impact on the actual speed of worldgen as that is pretty much exclusively tied to your CPU.
Skyrim had a similar problem when people started installing loads of custom high texture packs etc, hence the Skyrim reference in the OP. My knowledge of the specifics is a bit ropey too so take the above explanation with a pinch of salt. I do find it hilarious that the new DF with it's super high fidelity graphics
is having the same problem as Skyrim though. All hail Toady, Bethesda needed mods added to achieve this.
Edit: Kind of missed the point there didn't I. I don't want to contradict the author but I kind of agree that Dwarf Fortress game speed is not very RAM dependent as far as I know. I assume it should help with large embarks/adventure mode area transitions and things though, basically anything where the game is loading lots of information to and from memory rather than simulating tantrums/combat etc.
Edit 2: Hope I haven't made a fool of myself sounding like an expert when I'm not. Anyway, just wanted to say thank you very much for posting this Anticheese, it is just what I was looking for.