Recommended manual memory settings

Discussion in 'Windows Virtual Machine' started by rkowal, Jun 15, 2007.

  1. rkowal

    rkowal Junior Member

    Messages:
    15
    Hi

    I've come across a post that suggested turning "Automatic Memory limit" off in the preferences, and enabling "virtual memory preallocation", for better performance.
    I then started to wonder what would be the best setting for a Windows XP VM with 512MB...
    but to my surprise couldn't find anything resembling an "official" recommendation in these forums.

    So, should I put the limit to 768MB, less, more? What are your experiences with an XP install with 512MB? Or should I not bother and just leave the "Automatic" setting on?

    Thanks

    Robert
     
  2. rkowal

    rkowal Junior Member

    Messages:
    15
    P.s.

    I forgot to mention that my Guest machine, a MacBook Core Duo has 2GB ram.
     
  3. wingdo

    wingdo Pro

    Messages:
    314
    I've found that if I am only ever going to run 1 VM at any given time, setting the manual setting to 128MB higher than the highest amount of RAM given to any VM works great. So if you have only the XP VM, and you have given it 512MB RAM, set the manual selection to 640MB. I've used this setup for the longest time with excellent results. I recently upped the RAM when I upgraded my MBP to 3GB, but the 512 / 640 setting worked like a champ.
     
  4. David5000

    David5000 Pro

    Messages:
    312
    Where do you find "virtual memory preallocation?"

    Thank you,

    David
     
  5. wingdo

    wingdo Pro

    Messages:
    314
    Parallels Preferences (not VM preferences), memory tab, checkbox at the bottom.
     
  6. David5000

    David5000 Pro

    Messages:
    312
    In my setup (Parallels 2.5.3188) I have "Adjust reserved memory: Automatically/Manually."

    Maybe that is what the OP meant by "virtual memory preallocation?" (If so, I was misled by the quotes--I was looking for those actual words.)

    David
     
  7. wingdo

    wingdo Pro

    Messages:
    314
    virtual memory preallocation choice was added with 3.0, so that explains why you cannot find it. :)
     
  8. rkowal

    rkowal Junior Member

    Messages:
    15
    Thanks, wingdo, for the advice and clarification.
    By the way, I've just discovered that I cannot actually activate the "Enable virtual memory preallocation" option. When I do and start up the VM, I get the following error message:

    "Parallels Desktop failed to allocate the specified amount of memory.
    Please restart Parallels Desktop and try again.
    To avoid this problem in the future choose from the menu: Parallels Desktop > Preferences. On the Memory tab select the "Enable virtual memory preallocation" option."

    But I had copious amounts of free memory when I did this (676 MB free, 523MB inactive), and no amount of restarting (even rebooting OS X), changed anything.
    Hmmm???

    Robert
     
  9. David5000

    David5000 Pro

    Messages:
    312
    Thanks--I suspected that's what it might be.

    David
     

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