set HKCU\Software<a href="file://ESRI//Geodatabase//NetworkDataset//MemSizeToUseInBuilding" target="_blank">\\ESRI\\Geodatabase\\NetworkDataset\\MemSizeToUseInBuilding</a> (DWORD) to be a value less than 2000. The value set should also be less than the amount of available RAM you have so you don't swap to disk. A value of 256 or 512 should be more than adequate.