HELP: Parallels 6, performance issues for host

I've installed Parallels 6, and I must say that for a Windows XP guest, there's a marked improvement in performance and over-all responsiveness. Parallels 3 was fast, but 4 and 5 were major disappointments. 6 seems to have solved a lot of the regressions.

One problem that I'm having is with host performance. Even when I set Parallels to optimize for Mac performance, doing anything with Mac applications (like using Safari) is an exercise in extreme patience. If I forget to close Safari before booting the guest OS, it'll take 10 minutes for Safari to close. In fact, the whole Mac UI tends to freeze a lot and is generally sluggish. The dock takes several seconds to appear, as do menus, and switching apps takes a long time. (Meanwhile, guest performance is affected, but primarily for anything to do with disk I/O, while the guest UI is still fast and responsive.)

I THINK that the main problem is that I'm hitting swap heavily. My host (a 2.33GHz Core 2 Duo MBP) has 3GB of RAM, while I've allocated 1.5GB to the guest. You would think that would work out well, but it doesn't.

If I try to do ANYTHING with the host (like use Safari or an IM client), everything slows to a crawl. I notice, for one thing, that the "wired" memory jumps from 400MB to 2GB, which suggests to me that the VM has locked down the guest memory, preventing it from being swapped. This seriously chokes everything else. Before starting a VM, kernel_task is usually less than 100MB of real memory, but after starting a VM, it jumps to over 300MB and STAYS that way, even after the VM is shut down. On top of that, prl_vm_app uses about 250MB of real memory.

All of this adds up to serious thrashing, making the host quite unusable. It seems that Parallels works fine if it's the only app running, but in that case, why wouldn't I just use Boot Camp?

I haven't seen others complain about this, so I'm thinking that perhaps I have something misconfigured. Would anyone out there be able to help me figure out why Parallels doesn't seem to be playing nice with host processes?

Thanks in advance.

 

I have also noticed using Activity Monitor the Real Memory increases of Parallels Desktop 6. Each running virtual machine (prl_vm_app) takes about as much Real Memory as has been allocated in the virtual machine RAM configuration. Running more virtual machines than you have RAM for causes performance to go to hell. I have 14 GB of RAM. Using virtual machines that total more than 9 GB of Real Memory causes performance to drop to near zero. I usually only run one virtual machine at a time so it's not a big problem. I only use more than one virtual machine when I want to quickly look at a feature in a particular OS so what I've done is decrease the virtual machines RAM to 1 GB each and 1 CPU each so they can run together again.

I think you need to decrease your virtual machine RAM to 1 GB or less. Have you tried the "Enable Adaptive Hypervisor" option in Virtual Machine -> Configure -> Optimization?

In the .pvm virtual machine bundle/package, Parallels Desktop 5 creates a .mem file equal in size to the virtual machine RAM setting. In Parallels Desktop 6, the .mem file is zero bytes and there's a new .mem.sh file which is only 30 or 40% the size of the virtual machine RAM setting.

I guess this new RAM method accounts for some or most of the performance increases in Parallels Desktop 6. It's a double edged sword though.

 

I might be wrong on this, but I thought that Parallels used to have some kind of setting to limit how much memory Parallels was using from the host, independent on what the VM was configured for. Is this correct and is this setting gone from Parallels?

 

Still need more suggestions

I'll consider decreasing the RAM allocation, but it seems like Parallels is really playing unfair with resources. The VM pages should be swappable.

I do have the adaptive hypervisor enabled.

And I don't see any option to limit Parallels' use of memory.

 

There was an option in Memory Preferences in Parallels Desktop 5:
http://download.parallels.com/desktop/v5/docs/en/Parallels_Desktop_Users_Guide/22624.htm
I don't know a solution except to use a Mac that supports more than 4 GB of RAM.