Optimal Memory Size Confusion..

Discussion in 'Installation and Configuration' started by jvalal, Nov 9, 2007.

  1. jvalal

    jvalal

    Messages:
    5
    I have 2GB on my Mac and want to allocate half, 1GB to Windows Virtual Machine. But the text says that the optimal size is 512. Why wouldn't more memory be better for the machine? I am also planning on upgrading to 4GB. Will 512 still be the optimal amount.


    Confused
     
  2. Eru Ithildur

    Eru Ithildur

    Messages:
    1,954
    Between 512 and 768 MB is the best with 2 GB, and with 4 GB it is likely the best.

    The reason is that Windows does not usually effectively use all the RAM you give to it, even on physical machines. If you do plan on running programs like PS and other RAM intensive programs, I would up the RAM to 1.5-2GB when you get the 4 GBs.
     
  3. David5000

    David5000

    Messages:
    312
    I thought it also had to do with the fact that OS X needs the RAM to run the guest OS within Parallels?

    David
     
  4. Eru Ithildur

    Eru Ithildur

    Messages:
    1,954
    That too, it is the suppressed premise.
    Windows doesn't use it anyway, and therefore might as well give it all to OS X so it is able to run faster. OS X can creep along with 512 MB, but if it is between giving RAM that isn't used by Windows and RAM that is used by OS X, the choice is a no-brainer.
     
  5. jvalal

    jvalal

    Messages:
    5
    Still Confused

    I updated my system to 4gb of RAM and I still can't allocate more than 1GB. Am I missing something? I still run Office in XP, until Mac2008 officially launches, so I need more RAM for those programs.

    Please advise

    Thanks
     
  6. Alicia

    Alicia Parallels Team

    Messages:
    683
    Hello,

    as for memory, Parallels allocates Virtual Machine's RAM as one integral file. Consequently when your Mac’s RAM is too defragmentated (when too many applications are launched) then there could be not enough space in one sector for this file. I mean Parallels takes RAM (previously allocated to the VM in the settings) as one piece, not from here and there getting the neccessary amount all in all. So, as you can see, if you allocate not too much memory to your VM it would be easier to find a whole piece of this amount in the whole RAM when other applications are running (btw they take RAM by pieces not one after another but in different parts - that's why I called Mac's RAM defragmentated).

    jvalal, sre you trying to set RAM for the VM or for the whole PD?

    Best regards,
    Alicia.
     
  7. jvalal

    jvalal

    Messages:
    5
    Optimal Memory Size Confusion

    I open up parallels and click on the memory icon to change my memory. The slider shows that I can allocate 0 - 2048 on the scale. However, when I try to allocate more than 1000 it doesn't let. me. If I can' allocate more than 1000 than don't show me the 2048. I have 4GB in there so it shouldn't be an issue.

    Please advise.
     
  8. Alicia

    Alicia Parallels Team

    Messages:
    683
    Hello,

    please, check the Memory tab in Preferences menu for Parallels Desktop. It would be better if you attach two screenshots - for Memory tabs of Preferences and Configuration Editor.

    Best regards,
    Alicia.
     
  9. callsignAPOLLO

    callsignAPOLLO

    Messages:
    3
    Ok here's my specific problem...

    I have a top of the line new imac, 4gb ram etc... now, I am running a parallels machine off of a bootcamp partition and parallels is not starting up or performing fast enough for it to be comfortable to use.

    I have the "optimal" ram set around 500mb or whatever, should I set it higher?

    And, could anyone direct me to where the optimal settings are posted for my specific configuration, I plan on using the Windows stuff mostly when I'm using parallels but a little of the mac stuff too....
     
  10. John@Parallels

    John@Parallels

    Messages:
    6,343
    The optimized settings are
    1. Not more 50% of memory than on Host, so 1.5 GB for Windows XP should be OK
    2. Try to set antivirus settings for not to high for heuristic scan (details are vary for various so contacting vendor support is Ok)
     
  11. callsignAPOLLO

    callsignAPOLLO

    Messages:
    3
    i read that running parallels off of an existing bootcamp partition is slower than making a new virtual machine etc..

    is this true?
     
  12. John@Parallels

    John@Parallels

    Messages:
    6,343
    No, in case of Boot Camp you are avoiding disk virtualization level
     
  13. callsignAPOLLO

    callsignAPOLLO

    Messages:
    3
    ok..., then why does my parallels bootcamp machine thingy take forever to startup; almost 5min! And it seems quite slow inside, all applications are sluggish, especially when opening..?
     
  14. John@Parallels

    John@Parallels

    Messages:
    6,343
    It is,
    Because you are receiving message that driver initialization will take up to 5 minutes
     

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