How many iMac cores for Parallels Windows 7?

Discussion in 'iMac' started by doxavita, Jul 2, 2011.

  1. doxavita macrumors 6502a

    Joined:
    Jul 6, 2010
    #1
    I have a 2011 27"iMac with core i5 (3.1 Ghz), how many cores should I assign to my Boot Camp partition linked to Parallels 6 (Windows 7 Home Premium 64-bit)
     
  2. nightfly13 macrumors 6502a

    nightfly13

    Joined:
    Jul 17, 2008
    Location:
    Ranchi, India
    #2
    FWIW, I think it depends a lot on what you're using the two OSs for. If you'll keep Windows open a lot in the background and use OS X a lot simultaneously, then just give Windows 1 core. But there are lots of variations on this, you might use the Windows most of the time while it's open and then you can do the opposite.
     
  3. doxavita thread starter macrumors 6502a

    Joined:
    Jul 6, 2010
    #3
    So I can change this accordingly, right now I assigned 2 out of the available 4. Lets see how this plays out. I can always change this settings, no risk of deactivating my windows 7 due to hardware changes? what about the RAM? I have assigned 6GB out of 12GB, again, no problem if I change it sometimes?
     
  4. AppleDApp macrumors 68020

    AppleDApp

    Joined:
    Jun 21, 2011
    #4
    If they are opened simultaneously and you intend to fully use windows for some more ressource intensive work I say use 2 cores.
     
  5. AppleDApp macrumors 68020

    AppleDApp

    Joined:
    Jun 21, 2011
    #5
    They're shouldn't be any issues in changing the hardware allocations. Unless you change the size of your windows partition.
     
  6. sjinsjca macrumors 68000

    sjinsjca

    Joined:
    Oct 30, 2008
    #6
    Unfortunately, quite false.

    Specifically regarding the OP's question: Windows will detect if you change core count. You will need to re-activate Windows.

    Based on my experience, you can change the allocated RAM, and the disk size, but not core count, and you may have activation issues if you change 3D acceleration setting.
     
  7. doxavita thread starter macrumors 6502a

    Joined:
    Jul 6, 2010
    #7
    Well, I just changed it from 1 core to 2 cores, no activation issues yet, I'll keep my fingers crossed...
     
  8. basher macrumors 6502

    basher

    Joined:
    May 27, 2011
    Location:
    Glendale, AZ USA
    #8
    I assigned 4 cores and 4GB of RAM. No performance hit on the Mac side. I figure OS X is smart and mature enough on how to prioritize tasks and manage memory.

    My system is a 2011 iMac. 3.4ghz with 8th RAM.
     
  9. Gene S macrumors member

    Joined:
    Sep 24, 2010
    #9
    I'm sorry, but that is absolutely false.

    Through the various builds of Parallels 6, I've changed from 1 to 2 cores and back to 1, numerous times. I've also upgraded the memory, twice. Windows 7 has detected the changes, but not once have I had to re-activate Windows 7.

    (For some reason, some Parallels builds give me a blue screen upon startup. Changing the number of cores fixes it.)
     
  10. MythicFrost macrumors 68040

    MythicFrost

    Joined:
    Mar 11, 2009
    Location:
    Australia
    #10
    Whatever you do, don't assign four (you've only got four). Two should be enough for work, one for light use.
     
  11. sjinsjca macrumors 68000

    sjinsjca

    Joined:
    Oct 30, 2008
    #11
    I only posted that because it happened to me. I'm using Fusion-- maybe that's the difference?
     

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