I was reading up on Windows memory management the other day and had an idea - you know, I bet I can figure out whether those large address aware mods actually work.

SHORT VERSION
They don't work. They do correctly enable the game to access up to 4GB of memory, but game never touches the extra memory. I suspect their internal heap management algorithm just grabs all the memory they can at startup, up to 2GB, but no more. To make it actually use the extra memory space, a streamline-like hack that replaces the entire heap management system would be necessary.

LONG VERSION
Using http://technet.microsoft.com/en-us/sysinternals/dd535533 from System Internals, I captured a picture of memory for the scenarios of a http://www.quartertothree.com/game-talk/showthread.php?t=65955 and unmodded game, with and without the 4GB/LAA. I'm using the http://nvse.silverlock.org/ NVSE loader.

Unmodded 2GB:
http://imgur.com/1Kpwv

Unmodded 4GB:
http://imgur.com/pR9kh

Modded 2GB:
http://imgur.com/XO4W7

Modded 4GB:
http://imgur.com/Ut1NK

As you can see, mods do consume more memory, but when the 4GB flag is enabled the game doesn't even try to touch the extra 2GB of memory.

Well, all i know is without the 4gb patch modded Oblivion crashes in less than 10 minutes in :shrug: Also Fallouts do seem to perform better with the patches. It's possible that's just a placebo effect, though :hehe:

It's possible that for those two games + streamline's heap replacement it works, I haven't checked them. It definitely has no effect on the current version of FNV, however, with or without the current version of http://www.newvegasnexus.com/downloads/file.php?id=34832.