Hi Tharanga,
I think you're referring to the System Virtual Address Space (VAS). You don't mention whether your Windows 7 is a 32 bit or 64 bit operating system. To check that, go to your Control Panel, then click on System & Security. Then go to System. At System
Type, you should see whether your system is 32 bit or 64 bit.
If it is 64 bit, then you get a 4 GB VAS when running the System & applications. So, one would generally shut down all unnecessary applications when running FSX, which uses a large amount of VAS under certain conditions.
If it is 32 bit, then you get a 2 GB VAS, which makes it very difficult to run FSX properly & will often give an OOM (Out of Memory) or other error. There is a way to increase the VAS on 32 bit Systems but
not on 64 bit. Increasing the VAS on 32 bit systems, will give you another 1 GB, which makes it 3 GB; this is still quite low but better than 2 GB.
To avail of this extra GB, you will need to apply a 3 GB Switch. Go to Command Prompt (Admin).
Don't do this if your system is 64 bit. At the Command Line, write the following:
bcdedit /set IncreaseUserVa 3072
(Note: the space before '/ ' , before 'Increase' , and before '3072' (without quotation marks).
Exit Command Prompt & Restart the computer.
If you need to revert back to 2 GB and disable the Switch, then go back to Command Prompt (Admin), and type the following in the Command Line:
bcdedit /deletevalue IncreaseUserVa
(Again, note: the space before '/ ' and before 'Increase' (without quotation marks).
Exit Command Prompt & Restart the computer.
However, remember that your VAS usage fluctuates when using FSX, depending on how much scenery, LOD radius, clouds, vehicles, etc. that it has to read. So, whether you have a 32 bit or 64 bit system, it's best to disable any third party scenery that is
not being used and lower settings generally, especially when on approach or landing. This is when most errors occur as FSX VAS is already full & it shuts down.
Sometimes, it helps (when your VAS is running low on approach), to save your flight & shut down FSX. Then restart it and continue with the flight. I realise that this is not the best, but it can help if you're still getting errors with the 3 GB Switch
or 4 GB system.
Chris