Using 3150, but I'm pretty sure prior versions have this problem too. Scenario: 1. Open a VM and run it for a while. 2. Pause the VM and hide it. 3. Use other apps on your mac for a while, making sure to use apps that gobble lots of memory. At this point, most or all of Parallels.App and the VM's data has been swapped out to Mac OS X virtual memory. This is fine, and how VM should work in OS X. Now... 4. Go back to your VM and un-hide it. 5. Un-pause it. Result -- your mac will totally freeze / beachball, as OS X swaps back in the Parallels.app and the VM's data, and swaps out some of your other OS X apps to make room. This is ok, but based on the amount of time it freezes up, I'm pretty sure that it is swapping back in 100% of the memory, which is not right, and is definitely not how things worked in VPC. The problem here is twofold- A -- it takes a long time to swap out 800MB+, and your mac grinds to a halt while it's happening. B -- a good chunk of that 800+MB is not actually needed, meaning that if you switch back to a mac OS X app, some of that 800+MB has to be swapped back out. How to fix it -- Parallels should fix their VM paging behavior so that only the memory pages actively in use under the VM are swapped back in. In the case of a regular Windows XP or Vista install, this will be far less than 100% of the total memory. Only the current "working set" needs to be swapped back in immediately. Other pages will be swapped back in during the natural sequence of using the app. Perhaps this should be a user-controlled setting with two values: "When I un-pause a VM, please force swap 100% of the VM's memory" "When I un-pause a VM, only swap as needed" Thoughts?
