Windows 7 in bootcamp on 2015 15" rMBP?

Discussion in 'Windows, Linux & Others on the Mac' started by Iphone4sinwhite, May 26, 2015.

  1. Iphone4sinwhite macrumors 6502

    Oct 24, 2011
    I have read that the 2015 13" rMBP won't run windows 7 in bootcamp. The 13" has the newer broadwell chip while the 2015 15" carries on with the haswell chip. Does this mean that the 2015 15" rMBP will allow windows 7 to be installed in bootcamp (for later use in parallels)?
  2. snaky69 macrumors 603

    Mar 14, 2008
    You can use parallels without having a bootcamp partition, so if you only intend to use a virtual machine, you don't need it. In fact, you're hindering virtual machine performance slightly due to that.
  3. Iphone4sinwhite thread starter macrumors 6502

    Oct 24, 2011
    Thank you snaky. I'm not sure I understand what you're recommending. On my current late 2011 MBP I have windows 7 installed in bootcamp on a separate portion. I access this via parallels while in the Mac OS. I need windows 7 to run MathCad which is a pretty power intensive application. Is there a better way to do this?
  4. snaky69 macrumors 603

    Mar 14, 2008
    I think you don't quite understand how virtualization works.

    Running your bootcamp partition inside parallels is completely negating any advantage you have by having a bootcamp in the first place.

    To run at the computer's full power you need to be actually booting windows by holding the alt key at startup. Else you're using only virtualization which means MathCAD only has the power you allow it to have with Parallels' settings.

    Virtualization means your computer is running 2 complete OS'es at the same time, effectively halving available power to either OS.

    TL;DR, you're wasting your time.
  5. Iphone4sinwhite thread starter macrumors 6502

    Oct 24, 2011
    I apologize, I'm not using parallels, I'm using VMware fusion. I assume that doesn't change any of your points.

    What you're saying is that unless I run each OS completely seperately and alone, each will only get half of the available resources (8gb of ram instead of the full 16gb). I'm okay with this, I use Yosemite for most things and if I have to do some work in MathCad I'll run fusion for a few hours and then close it.

    Is it possible to use windows 7 through fusion (not on bootcamp) and not have to split resources between the two OSs?
  6. snaky69, May 26, 2015
    Last edited: May 26, 2015

    snaky69 macrumors 603

    Mar 14, 2008
    No. It's an either or situation. How much each OS has is what you have allowed it to have in your virtual machine's settings.

    Either you boot straight into windows, or you split your resources through virutalization.

    In your case, if you never boot into windows your bootcamp partition is more of a hinderance than anything else. I'd advise to go straight for a virtual machine, which can easily be backed up and used on another computer, a thing you cannot do using bootcamp.
  7. wct097 macrumors 6502

    Nov 30, 2010
    It can be argued that the ability to dual boot and run the bootcamp partition inside of VMWare is indeed a benefit in and of itself. You can use a single setup in both places. You may want to boot into Windows to do more graphics intensive stuff, but run VMWare within OS X when you just need to run a Windows program and don't want to reboot.

    I personally prefer to use the power of VMWare to have portable virtual disk files and snapshots. It makes backing up the Windows partition substantially easier. That way you can actually back up to Time Machine, which wouldn't work with a Bootcamp partition.
  8. Iphone4sinwhite thread starter macrumors 6502

    Oct 24, 2011
    Thanks wct097. Currently I give 8gb and 250gb to the bootcamp partition. If I am not using fusion or logged into bootcamp/windows, is the full 16gb available to Yosmite? If I choose not to have a bootcamp/windows partition on my new Mac and instead use a virtual machine in fusion to run windows 7 can Yosemite use all 16gb when the virtual machine is not activated?

    Also, this is assuming windows 7 can be installed in both bootcamp and a fusion virtual machine on a 2015 15" rMBP.
  9. wct097 macrumors 6502

    Nov 30, 2010
    When you're booted into OS X, the bootcamp partition is not using your RAM or processor resources. Likewise, if you're using a VM, the Windows VM isn't using RAM or processor resources when turned off, only while running.

    You're limited to how much memory you can allocate to the VM. It has to be somewhat lower than the max the machine has. Any memory allocated to the VM will be tied up for the entire machine while the VM is running.
  10. snaky69 macrumors 603

    Mar 14, 2008
    1. You probably mean your settings in VMWare? You cannot assign an amount of RAM to bootcamp. When booted into bootcamp, your computer is using all the resources available. When used through VMware, you can assign an amount of RAM to Windows.

    2. Yes, of course it is.

    3. Yes, of course.

    I will repeat my prior post. If you never actually use bootcamp (as in, you boot into windows, not OS X) then don't bother installing it.

    You'll save the hassle of having a fixed partition size, you will be able to backup your Windows install alongside OS X. You'll also be able to have VMWare dynamically assign an amount of disk space depending on the needs of Windows. Meaning it will only use as much as it needs, no more.
  11. yjchua95 macrumors 604

    Apr 23, 2011
    GVA, KUL, MEL (current), ZQN
    No. It's not because of Haswell or Broadwell - it's because of the EFI chip in the motherboards. In the new 15" rMBP, Apple also (highly possibly) changed the EFI chip to that of the one used in the Broadwell 13", thus removing BIOS-CSM support and hence locking out Windows 7.
  12. Iphone4sinwhite thread starter macrumors 6502

    Oct 24, 2011
    Thank you. It looks like the decision is made for me then. In order to use windows 7 on the 2015 rMBP I'll have to use a virtual machine in VMware fusion and enjoy the benefits of no HDD partition, use of all ram, and the ability to back up the virtual machine.

    It seems there is no disadvantage to using virtual windows 7. Will mathcad run just as well in a virtual machine as using fusion to access it in bootcamp?
  13. yjchua95 macrumors 604

    Apr 23, 2011
    GVA, KUL, MEL (current), ZQN
    It'll run, but it won't run all that well since VMware can only use a for of emulated graphics and can't use full resources.

    What's wrong with Windows 8? Besides, Windows 7 doesn't support retina scaling.
  14. dmccloud macrumors 6502a


    Sep 7, 2009
    Anchorage, AK
    This is the big advantage of Windows 8 on retina Macs. It runs and looks so much better with scaling, and apps that have not updated to take advantage of scaling suffer due to their oversight/lack of interest in updating.
  15. snaky69 macrumors 603

    Mar 14, 2008
    You'll see no difference, or marginally better performance. You were already running a virtual machine, you were simply using the more restrictive method of having one by having a bootcamp partition that is strictly accessed through VMWare.

    That's what I'm trying to get through to you, maybe I'm not conveying my thoughts well, English isn't my first language.

    The whole point of Bootcamp is to make a disk partition, so that you can install Windows onto it and boot INTO windows. Doing so would make your computer run solely on Windows when booted that way. Just like a normal Windows-based PC(Dell, Lenovo, you name it). Since only Windows is running, all the computer's resources(and thus, performance) are available to it. You can reboot the computer and go back to OS X once whatever it is you needed Windows for is done.

    Same goes for OS X. If you are booted into Yosemite, then all the computer's resources (and performance) is available to Yosemite.

    When you use VMWare fusion, the program uses the settings you chose to allocate resources to Windows, while OS X is still running. What that means is that if you have 16GB of RAM, and you let VMWare give 8GB to Windows (in your case, the bootcamp partition you are using as a virtual machine) then only 8GB is available to Windows, and only 8GB is left for OS X. Same goes for the number of processor cores you let it use.

    If I understood you correctly, you used Bootcamp to install Windows on your machine, only to run it strictly through VMWare fusion afterwards. If that is indeed the case, then you took the long way around, and gave yourself less freedom with your virtual machine than if you'd gone 100% virtual from the getgo.

    The bootcamp partition cannot be backed up through Time Machine if you use that. Should it ever become corrupted and you use no other means of backup, any data on that partition will be lost forever.

    A truly virtual machine resides as a file on your hard disk. If you let VMWare do its thing, it will dynamically grow or shrink that file according to how much space your virtual machine requires.

    The advantage is that since it is just another file, it can be easily backed up through time machine, and as a bonus, you don't have a partition with a set size taking up room in your hard drive, even if half of it is empty space.

    I hope I explained things correctly.
  16. Iphone4sinwhite, May 28, 2015
    Last edited: May 28, 2015

    Iphone4sinwhite thread starter macrumors 6502

    Oct 24, 2011
    Snaky69: thank you for this excellent synopsis. Your English is perfect, my knowledge of virtual machines is not. I will definitely follow your recommendation and avoid the separate partition.

    I guess one other question; is it possible to copy my windows 7 disk to a jump drive or SD card so that is can be installed as a virtual machine on a SuperDrive less Mac? In the last I've used the SuperDrive on my cMBP to install software on the newer MacBook pros and airs but I won't have that option this time.
  17. wct097 macrumors 6502

    Nov 30, 2010
    Yes. Create an ISO from the Windows 7 disk and VMWare can treat the ISO as a disk loaded in it's virtual optical drive.

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