Re: New versus old NONMEM

Koen, > What are the advantages of NONMEM7 with respect to older versions like V and VI? Automatic computation of eta and epsilon shrinkage. The default objective function display format is easier for humans to read (this can easily be implemented in NONMEM VI by changing the source code). > Is it still "acceptable" to use versions V and VI nowadays? I consider NONMEM V is obsolete and people still using it either are using an unlicensed version or have terrible IT support. NONMEM VI release 2 is the most reliable version. There are bugs in NONMEM 7 that are not present in NONMEM VI (e.g. see recent email from Paulo Denti). In my experience NONMEM VI is generally faster and uses less memory than NONMEM 7 which is a big advantage on multi-core machines. I can only run 3 problems with NONMEM 7at the same time but I can run 8 problems with NONMEM VI on the same 8 core machine. The next version of NONMEM 7 is expected to fix this memory problem but it remains to be seen if it faster. > Is there an "optimal" combination of NONMEM, compiler and operating system? The fastest compiler I know of is Intel Visual Fortran for both NONMEM VI and NONMEM 7. There are occasionally differences in results between compilers but I don't know of any systemic study that would favour one compiler over another in terms of accuracy and consistency of results. I am not aware that the OS makes any difference to the way that NONMEM runs if the same compiler and hardware are used. Some virtual machine hosts may be slow down runs e.g. I find that intensive disk activity e.g. creating simulation table files with Windows 2003 running as a virtual machine on top of Xen server is much slower than a native Windows 2003 installation. The main thing is to use the fastest CPU you can find! Nick