12gb of ram. How much for win7 & how much for osx?

Discussion in 'iMac' started by EnterTheSwamp, Aug 16, 2010.

  1. EnterTheSwamp macrumors member

    Joined:
    Jun 29, 2010
    #1
    I just purchased an i7 Mac with 12 gb's of ram and was going to be running parallels on it. How much ram should i dedicate to each system? Will it only use the ram allocated to windows if I have parallels open?
     
  2. xraydoc macrumors demi-god

    xraydoc

    Joined:
    Oct 9, 2005
    Location:
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    #2
    Yes to the second part. Unless Parallels is open and your VM is running, all the RAM will be available to OS X.

    As for the first question, I guess it depends on what you plan on doing within your Windows virtual machine.
     
  3. HobeSoundDarryl macrumors 603

    HobeSoundDarryl

    Joined:
    Feb 8, 2004
    Location:
    Hobe Sound, FL (20 miles north of Palm Beach)
    #3
    I pretty much have that exact same setup. I chose to allocate 2 cores and 4GB of the 12GB ram to Windows 7 64 bit. So far it has been more than enough for everything I do in Windows.

    Installed it as a boot camp partition on the SSD, then used Parallels 5 to create the VM using the boot camp installation. That works really well, and it seems very fast booting W7 from the SSD.

    You can always change the hardware allocations in Parallels if your initial guess is wrong.
     
  4. newdeal macrumors 68020

    Joined:
    Oct 21, 2009
    #4
    ...

    Yeah i would probably do 4 for windows and 8 for osx. Even though osx seems to manage memory better i find it easier to go through a lot of memory because most programs stay open in the dock when you close them unlike windows. Also if you are web browsing i assume you will do that in osx and safari can eat up the memory pretty well
     
  5. Poob Bubes macrumors 6502a

    Poob Bubes

    Joined:
    Apr 16, 2007
    #5
    Many people have the feeling of "more is better," but when it comes to RAM in the virtual machine, that is not necessarily the case. More RAM means longer virtual machine launch times, suspends and resumes. For most users, 512MB to 1GB of virtual machine RAM will work best. Use more than that only if you really know you need it.

    Source: Head-to-Head: Parallels Desktop for Mac vs. VMware Fusion

    What's important to note: your VM should have 1 CPU max and no more than 25% of your total RAM. In other words, if you have a Apple MacBook Pro MB990LL/A 13.3-Inch Laptop or similar model, or iMac with 4GB RAM, you should give the VM 1GB and no more. Parallels itself should be allocated no more than 2GB and told to balance the RAM usage. Why do I recommend these settings? Because any more and your Mac will suddenly not be so fast.

    There is a reason for this. When you're dealing with Windows, there are a lot of background writes and drive accesses and paging that takes place. If you give Windows a lot of RAM, it will thrash the drive paging an equal amount of disk space. That thrash, combined with the RAM usage (which is now not available for the Mac OS), will cause your computer to slow to a crawl. It's not nearly as noticeable if you've got 8GB RAM and a 7200 RPM drive, so if you do decide to upgrade your computer, then you can bump up the specs...but I still stand by the 25% of RAM rule (meaning 2GB max) and 1CPU for the best results.

    Source: Amazon.com review of Paralles 5.0 by M.D.C. "The Franchise" (San Diego, CA)
     
  6. EnterTheSwamp thread starter macrumors member

    Joined:
    Jun 29, 2010
    #6
    I am a little confused. The iMac I ordered has 12gb, 4 cores, and a 7200 rpm hdd. What didmyou meanly upgrading? Why only 1 core for the vm? What would be the down side of giving it the extra core?

    I was actually leaning towards 2 cores and 4gb of ram, but not if it will make it slower.
     
  7. HobeSoundDarryl macrumors 603

    HobeSoundDarryl

    Joined:
    Feb 8, 2004
    Location:
    Hobe Sound, FL (20 miles north of Palm Beach)
    #7
    Also, I have the same i7, and Parallels 5 offered me the option of allocating up to 8 cores for Windows, which I assume is the 4 physical and 4 virtual cores in the i7. I chose 2 cores.

    At least so far, Window 7 seems crazy fast in Parallels 5 as in boot camp. I don't notice the slowdowns described.
     
  8. darlenea macrumors member

    Joined:
    Aug 19, 2010
    Location:
    Minnesota
    #8
    I am just switching to a MAc for the first time and I have two programs I need to run in Windows - I have checked with theis companies and both will run in Windows 64 bit - I am interested in trying them both on Boot Camp and in Parallels and seeing which works best. Do I have to buy to copies of windows to try this? or does the qoute from above say I can put windows in Bootcamp and then access through Parallels/VM ware? The two programs i will be running in windows are ProShow Producer and FutoFusion. I will be using Adobe Creative Suite 5 on the Mac side.

    Hopefully this makes sense - I am trying to learn the Mac . THanks Darlene
     
  9. HobeSoundDarryl macrumors 603

    HobeSoundDarryl

    Joined:
    Feb 8, 2004
    Location:
    Hobe Sound, FL (20 miles north of Palm Beach)
    #9
    One copy of Windows installed (first) as a boot camp partition. Then, when you set up Parallels, you tell it to use that partition instead of installing Windows again.

    In theory, EVERY Windows program will run better in boot camp since that, in effect, makes your mac a Windows PC. Parallels always has to work like a middle man, so there should be a little bit of tradeoff in everything you try to do in Parallels vs. boot camp.

    That said though, the few programs that made me require Windows zip via Parallels such that I rarely go into boot camp.
     

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