High spec PC setup for NONMEM - recommendations?

Dear NMUsers We are investigating the purchase of a hyperthreaded dual quad-core machine (8 physical cores; hyperthreaded to create 16 logical cores) with a view to reducing the time taken for those aspects of model validation that require multiple iterations e.g. bootstrapping, likelihood profiling. Our current system uses NONMEM 7, with Intel Fortran running under Windows XP Professional, 32 bit machine . A licensed version of PLT Tools is used for graphical output and to facilitate model development and validation. We are wondering whether a 64bit operating system would be preferred for optimal performance e.g. 64bit Windows 7? Any comments or recommendations gratefully received. With thanks and best wishes Ann _______________________________________________________________________ Ann Rigby-Jones PhD MRSC Research Fellow in Pharmacokinetics & Pharmacodynamics Peninsula College of Medicine & Dentistry N31, ITTC Phase 1 Tamar Science Park 1 Davy Road Derriford Plymouth PL6 8BX _______________________________________________________________________