Asking this question again because nobody gave any helpful information. Ugridstoload tips doesn't count. So it's 1.4.21.0.4 version of Skyrim. Perfomance really improved but game still crashes at 1.98-2 gb ram usage. 4gb and other LAA junk patches do nothing, worked 2 or 3 times for me then game started to crash again. Another issue i've experienced - limit of ram usage by game is ~3.25 gigs because tesv.exe is 32 bit application and thing just freezes when ram usage gets to 3.300.792 KB. Using 2k textures and setting ugridstoload=11 makes game use 1.8-2.2 gb RAM. Game looks awesome when ugridstoload=13 and more but ram usage is always about 2 gigs so 90% of time game is unstable. PC version really needs 64 bit version application and some serious game engine improvements. Sorry for poor english.

Anything above uGridsToLoad=7 is unstable for me. As for the ram Its never used all of my ram fully neither and in essence you just answered your own question - its a 32 bit app!

A 64 bit exe would require a total engine overhaul, won't happen.

No 64bit wouldn't require a total engine overhaul...... *sigh*... it only needs the application itself to be recompiled at a 64bit application (cheap and easy way)..... with several rather small rewrites to make better use of 64bit (which would take a little more energy involved)... otherwise the engine is fine and intact as it is without much being needed to be changed... however using excess of 4gb would still be "not sure"

Some engines specially as old as this one is for what it is based on...... just has it's limits.

just like for example the unreal 2 engine that is still in use today with games.... has hit it's limits quite some time ago and it doesn't matter what you do to it.. it's just totally obsolete.

One thread is enough.
http://www.gamesas.com/topic/1339242-skyrim-really-cant-use-more-than-2-gigs-of-ram/