I was battling the dreaded out of memory "OOM" error on Vista 64 with 4Gb of memory and the august vista patch.With the PMDG 700X and Ultimate Terrain, there was no way with FSX SP1: I couldn't last more than 2 minutes in flight before being kicked out.I solved my problem by modifying my fsx.exe to use the large address space using this tool: http://ntcore.com/4gb_patch.php. Apply it to fsx.exe after you make a backup, and presto, no more OOM (for now).There is another tool on the same site that sets the "large address space" flag on the exe (CFF Explorer).Hope this helps.Etienne

Etienne,Have you installed Accel/SP2?Regards,Jim Karn

No I have not. This is a fix for SP1. When SP2 comes out (dissociated from the accel pack), I'm sure this will be "built-in".Etienne