Allocating More Than 4Gb RAM to P7 VM?

Discussion in 'Installation and Configuration' started by imacken, Sep 15, 2011.

  1. imacken

    imacken Kilo Poster

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    Can anyone tell me why when I have 16Gb RAM in my 2011 iMac on Lion, that whenever I try to give Parallels more than 4Gb, I get a message to tell me not to do it as it will slow all systems down?
     
  2. LeslieL

    LeslieL

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    I am also curious about this topic. I've 4GB of RAM and can only allocate 1.5GB to Windows VM. If I double my RAM to 8GB, will PD allow me to allocate 4GB to each OS ? And will that help me run graphics intensive games in Win 7?

    Appreciate those w 8GB RAM share their experiences.
     
  3. imacken

    imacken Kilo Poster

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    I had a chat with online support, and they definitely recommended I go no higher than 4Gb. That was the same recommendation when I had 12Gb RAM. He said because Windows is working in a virtual environment, that it only needs max 1-3Gb. Don't know why it tells me in the software that 4Gb is optimum, but there you are.
    WRT to graphics intensive games, P7 has been a big improvement on that front.
    I can run things like F1 2010 perfectly OK, but The Witcher 2 struggles with frame rate, and Deus Ex HR works OK once the textures are loaded. It has a pause regularly when looking at a different scene, but once it's going, it works reasonably OK.
    As usual, it's a toss-up whether to reboot and run in Bootcamp. There is no doubt that Bootcamp is better (obviously), but Parallels is gradually getting there!
     
  4. David Haynes

    David Haynes Bit Poster

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    What about heavier programs

    I use a program that requires 8GB if running in Windows 7 - I don't think 4GB would work.
    Parallels - what is the issue.
     
  5. imacken

    imacken Kilo Poster

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    Eh, what program is that!?! 8Gb to run!
     
  6. David Haynes

    David Haynes Bit Poster

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    Revit Architecture

    Autodesk's Revit Architecture runs best with 8GB. I have an iMac with 16GB and what I want to do is allocate 12GB to Windows 7 x64 and 4GB to OSX Lion.

    Is that so hard ?!?
     
  7. imacken

    imacken Kilo Poster

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    'Runs best' is not the same as 'requires'.
    You can allocate as much RAM as you like to Parallels. It's just that the experts are telling you that is not a good idea, presumably because an OS running as a VM has different requirements to when it's running 'native'.
    Maybe your best bet is to run in Bootcamp.
     
  8. David Haynes

    David Haynes Bit Poster

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    8GB max

    imacken - 8GB is the max you can allocate to Parallels - that is not as much as you like.
    Revit requires 8GB.
    I would love to use BootCamp - but I don't have a boot camp partition right now. I really didn't want a dual boot situation.

    My question remains - why can't those of us who have more RAM, use the RAM as we need.
     
  9. imacken

    imacken Kilo Poster

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  10. BobTheDog

    BobTheDog Bit Poster

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    Version 6 had no problem allocating more than 4GB.

    I have 8GB allocated and just ignore the warning, and bess I do need 8GB!
     
  11. imacken

    imacken Kilo Poster

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    Version 7 has no problem allocating up to 8Gb either. It's just that it is not recommended by the experts - same as in version 6.
    I think we have to get away from thinking about the RAM allocation as we would if Windows was running native.
    Don't you think that if performance would improve, that the Parallels engineers would recommend using as much RAM as possible? They would want to show their software in the best light possible.
     
  12. PattyZ

    PattyZ

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    could NOT in version 7

    My experience has been that I set the VM ram to 8 GB, and as soon as the VM starts, it kicks the RAM allocation back to 4 GB, even though I said 'I know you don't want me to do that, but I don't care, I'm doing it anyway'. I got one tech support person to tell me that I could try messing with MSCONFIG, which wouldn't let me allocate more than 4 GB even though it's a 64 bit OS. Then the next person in tech support told me 'wasn't recommended = not allowed' which was not a great answer.

    Any ideas out there? REALLY don't want to have to run bootcamp!
     
  13. Specimen

    Specimen Product Expert

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    PattyZ , how much real RAM does you mac have?
     
  14. PattyZ

    PattyZ

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    Revit has been much slower in Parallels than in Bootcamp. Just upgraded to 16 GB on the MAC, specifically for the purpose of allocating more than 4 GB to the VM.
     
    Last edited: Nov 11, 2011
  15. makeev

    makeev

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    I installed a 16 GB system memory to allocate for the Windows 7 8GB, but I can not do it. Now I have less than 500MB of free memory in the Windows, and I have not run a browser! Why can not allocate more than 4GB? Why then in the settings to show such a possibility?
     
  16. Specimen

    Specimen Product Expert

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    Is the Windows version 64bit?

    (Only 64bit Windows can use more than 4 GB RAM)
     
  17. makeev

    makeev

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  18. Specimen

    Specimen Product Expert

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    I'm glad you put a picture that shows the memory usage on your machine, Active and Wired memory are currently occupying about 10 GB and Inactive 4 GB, also, the yellow warning box shows the Parallels Machine is not stopped, is probably running or suspended, you can only change this setting in a properly shut down VM.

    So, close some programs (close Chrome), open the Terminal.app and type 'purge' (without quotes) press enter, this will purge inactive memory, make sure you get more than 8 GB of Free Memory (in Activity Monitor, the green slice).
    Now start Parallels, make sure the VM is not suspended, shut it down if necessary, you can only alter the RAM assigned to the VM once you don't see the yellow warning box on top.
     
    Last edited: Jun 14, 2012
  19. Teddy J

    Teddy J Bit Poster

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    Posted this question to apple.stackexchange.com

    If you use your machine as a real-world tool, living under x86 limitations seems to be an artificial limitation. Other virtualization products don't even consider putting such a limitation (i.e. VMware with vSphere, Fusion, etc.) because there shouldn't be such a limitation unless a) Parallels is trying to protect users from themselves or b) there's a limitation with Parallels product itself. The former is silly (and "experts say so" is not a valid justification) and the latter would be surprising/disappointing.

    I switched to running a MacBook as my daily machine because I could run all environments great on one machine (Windows, Linux, and Mac OS X as the host) with some great hardware. Bootcamp is not an option for me because I switch back and forth throughout the day. I ended up going with Parallels because the resume from suspend times were significantly better than Fusion's (hadn't tried VirtualBox because of some limitations in some areas that I couldn't work with). There are shortcomings in each package and I work around those in Parallels (flakey rendering at times with Windows 8, especially with Office 2013; flakey rendering on connected displays if using "Retina display" settings; no quick keyboard shortcuts to suspend/resume machines...as far as I can tell; no quick keyboard access to machine configuration settings; etc.), but this particular issue seems to be so unnecessary. I have yet to have found a straight answer from Parallels for what seems to be an arbitrary/out-of-date restriction (how many users really run x86 that much anymore?).

    Posted this request to http://apple.stackexchange.com/ques...s-parallels-8-recommend-max-4-gb-ram-for-a-vm
     
  20. MehdiES

    MehdiES

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    The really weird warning messages that Parallels Desktop displays when trying to allocate more than 4GB to a VM and the even weirder and non-sensical "advice" from Parallels Desktop support hint at a design flaw in Parallels Desktop. It's looking like they made a poor architectural decision early on that's now coming back to bite them hard. I'd love to see the code involved in this - it must be one beautiful mess.

    I wish Parallels Desktop would at least let us know what "performance issues" we can expect when using more than 4GB.

    For what it's worth, I'm currently using a Windows 8 VM in Parallels Desktop 8 with 6GB of RAM allocated to it without any issues. I'm using it as a my main dev machine with Visual Studio 2012, SQL Server 2012, IIS Express, SQL Compare and NHibernate Profiler. The host machine is a 15'' Macbook Pro with Retina Display with 16GB of RAM.
    It works like a charm and is ridiculously fast. Haven't noticed any performance issues in either Windows or OS X.

    But then this machine is so freakishly fast to start with that there could performance issues that I'm simply not noticing because it's still an order of magnitude faster than my previous machine.
     

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