I have noticed a lot of slowdowns and weird behaviour with Parallels and OS X, especially under low free memory conditions. This includes general lags, the dock becoming unresponsive and the dock bouncing choppy, early pageouts for no apparent reason,
and messages in system log like: IOHIDSystem: postEvent LLEventQueue overflow,
or the Dynamic Pager of OS X not being able to assign virtual memory swapspace,
and iTunes stuttering when playing music at the same time Parallels is loaded.
Trying to solve the issue I discovered that USB Overdrive is to blame in my case at least.
After I removed it, no more problems! I even stressed the system to the point of 200.000 pageouts and no physical memory left free, with 3 Parallels VMs loaded, all Adobe CS3 suite, Safari, iTunes playing, and everything was working, slow but steady.
After I closed the programs everything returned back to normal, where with USB Overdrive installed the general chopinness remained, especially in the Dock, until I restarted my Mac. Something goes very wrong between the ConnectUSB.kext that Parallels loads, and the USBOverdrive.kext.
Without wanting to advertise, I found another much more modern mouse driver, that has no such problems, and Parallels works like a dream after that, even on extreme low memory conditions.
I wonder how many of you guys that complain about choppiness and unstable Parallels, have USB Overdrive installed.
Last edited: Apr 21, 2007