1 is prepar3D more "easier" on memory than FSX? is it worth the effort to install all I have of US west coast (FTX, FSDT etc etc) ?
Can't see much difference in system requirements compared to FSX.
2 are your other US products less "heavy" on memory as KLAX?
As I've said already, KLAX is not particularly "heavier" than other products, only marginally so, it lies in what is an already complex area and is able to attract many AI, so people might be mislead thinking KLAX is the problem, when it's not.
However, you can save some memory by turning off the "HD Textures" in the Addon Manager. This will make the scenery look more blurred, but will probably save about 200-300 MB, which might be enough to complete a flight without crashing.
However, if you have exhausted all your RAM on a 64 bit OS, you simply have too many installed addons and/or TOO HIGH SETTINGS, turn them down.
I was never able to use more than 2.2 GB or RAM at KLAX, with the PMDG 737, and 100% AI Traffic with UT2 and very high scenery settings. Under a 64 bit OS you have 4GB available for each 32 bit app so, if your memory consumption is so high, there's something wrong in your settings (maybe you applied so "tweaks" that caused issues)
Here's some results from some tests I've made, demonstrating that KLAX is NOT the most memory-hungry item out there:
http://www.fsdreamteam.com/forum/index.php?topic=7285.msg62471#msg62471I see now the video in your main homepage (737 PMDG, Zurich, skies, rain) ... I'd like to know that system specs or at least its fsx.cfg ...
No idea, it's made by a forum user, we simply linked it from YouTube.