LR2 Vista Memory VERY LOW

Question

I have Vista SP1 with 4GB of Memory, ok I know I reallyt only have access to
a little over 3GB but LR is only making use of 712MB which is crazy low ....
WHY ?
And please don't tell me it has anything to do with fragmentation because
it's not.
Lightroom version: 2.0 [481478]
Operating system: Windows Vista Professional Service Pack 1 (Build 6001)
Version: 6.0 [6001]
Application architecture: x86
System architecture: x86
Physical processor count: 2
Processor speed: 2.1 GHz
Built-in memory: 3069.6 MB
Real memory available to Lightroom: 716.8 MB
Real memory used by Lightroom: 271.4 MB (37.8%)
Virtual memory used by Lightroom: 258 MB
Memory cache size: 0.3 MB
Application folder: C:\Program Files\Adobe\Adobe Photoshop Lightroom 2
Library Path: C:\Users\Michael\Pictures\Lightroom\Lightroom 2 Catalog.lrcat

Answer 1

If you have more than 3G in your 32-bit vista system you can override the app memory limit (2048MB) to allow LR & other apps like PS to allocate more memory:
bcdedit /set IncreaseUserVa 3072
reboot
Not sure whether the extra memory improves LR performance but it will now report it has 1228.8MB real memory available. Lower values dont appear to work (e.g. 2560)
This can be backed out if you aren't convinced:
bcdedit /deletevalue increaseuserva
reboot
XP has another way of dealing with this (refer to /3G switch in boot.ini)