On Apr 2, 2007, at 1:32 PM, john_p_ehmann wrote: > If you are seeing large amounts of virtual memory being used then > Yes, you are low on physical memory. I would reccomend adding another > GB if you could to minimize the use of virtual memory. When the > system has to turn to swap space (virtual memory) is has to write out > to the disk drive and this will increase the wait time for other disk > activities, such as recording audio etc. It may well be that the original writer doesn't have enough RAM, but the Virtual Memory size listed in Activity Monitor has nothing to do with that. In OSX, *all* memory (programs and data) is virtual, and some of it resides in physical RAM. The VM size listed for each process will not change regardless of how much real RAM you have; that number is simply the size of the overall memory image. Much of that VM size is actually the program as it resides on disk (in the Applications directory or wherever) and is not part of the swap space. Rather than loading the entire program into RAM when you launch it, the o/s simply maps the program on disk into VM, and chunks of the program swap in on demand--much faster and much more efficient than sucking in a huge program that only small portions of may actually run. (This is why the "page in" count is always nonzero in Activity Monitor, but the "page out" will be zero unless you really ran short of RAM at some point.) To tell whether you're swapping, look at the "page out" count under the System Memory pane in Activity Monitor. If it's nonzero, you've run short of RAM at some point since the last boot. If it is actively climbing, then you're short of RAM right then. If it's zero and stays there, you have enough RAM (and contrary to conventional wisdom, buying more RAM will *not* make things run faster.) Another option is to run "top -S" from the Terminal. The header looks like this: Processes: 76 total, 2 running, 74 sleeping... 221 threads 17:14:02 Load Avg: 0.50, 0.24, 0.21 CPU usage: 9.6% user, 13.2% sys, 77.2% idle SharedLibs: num = 207, resident = 57.1M code, 6.05M data, 25.1M LinkEdit MemRegions: num = 13464, resident = 612M + 23.6M private, 168M shared PhysMem: 150M wired, 261M active, 735M inactive, 1.12G used, 388M free VM: 7.87G + 137M 83021(0) pageins, 0(0) pageouts Swap: 0B + 64.0M free Purgeable: 12.6M 0(0) pages purged In this case, the second to last line shows that 7.87GB of VM is in use, but zero bytes of sap space are in use. (You'll note that there have been zero pageouts, so it makes sense that there's no swap.) --Dave