I've just run this patching program on my FSX & FS2004 exes and I will be doing so on others as well like Railworks.
http://www.ntcore.com/4gb_patch.php
What it does for 64bit systems is "patches x86 executables in order to let them have 4GB (instead of only 2) of virtual memory on x64 platforms. " So if you have a 64bit system it's worth a go to see if it shows improvements. It creates a backup of the exe but I did one myself as well just in case. I believe this will benefit older programs like those I mention. If it's a newer prog the flag might already be set anyway.
PS. Some other good utilities on that site as well.
64bit 4GB exe patcher program
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