Mac – Windows 7 64 bit VirtualBox VM slow on Mac OS Lion

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I'm running VirtualBox on my Macbook running Lion (Aluminum 2008, 4GB RAM 1067 MHz DDR3, 160 GB hard drive space, 2 GHz Intel Core 2 Duo) to run Windows 7 64-bit Professional Edition. Starting up the VM takes upwards of 4 minutes, and once I open up Visual Studio it becomes so slow it's unusable. I'm wondering it's my settings for the VM that's slowing it down. Visual Studio and Microsoft Visio are the only applications I'm interested in running.

Specs for the Windows 7
1024 MB for the base memory
Boot order: CD/DVD-ROM, Hard Disk
Acceleration: VT-x/AMD-V
Video Memory: 16 MB
IDE Secondary Master: Host Drive 'HL-DT-ST DVDRW GS21N
Processor(s): 1 CPU
Virtual Size: 40 GB (fixed size storage)

Should I adjust my RAM, virtual size, or the number of processors to make it run faster, or are my mac's specs just not enough to handle running a virtual machine? My macbook runs other applications pretty quickly (MATLAB, Eclipse, Photoshop run just fine). If it continues being this slow, I'm thinking of using Bootcamp to just install Windows 7 on a separate partition.

Best Answer

Have you checked to make sure your MacBook is starting Lion up in 64-bit kernel mode? You can use this tool to check that.

Lion, even though it's a 64-bit OS, capable of running 64-bit apps, can start it's kernel in 32-bit mode on certain older machines. This won't affect most 64-bit Mac apps. They still run in 64-bit mode and can use >4GB of memory. But depending on which kernel is being used, your virtual machine will run in either a 64-bit or 32-bit process since VirtualBox interacts with the kernel at a lower level than most apps.

I have an older MacMini (2007, which boots to a 32-bit kernel) with Lion and VirtualBox on it. I've noticed that the Mac itself still performs pretty well. A 32-bit WinXP machine with 1 CPU and 1024MB RAM works almost as if it were natively on the hardware (except for graphics).

However, when I put a 64-bit Ubuntu machine onto it (even Ubuntu Server), it uses about 30% of a physical CPU core when idle and works slowly. I checked the process type in Activity Monitor, and it was a 32-bit process. The same virtual machine is very snappy on my newer iMac (booting 64-bit), and uses about 6% of a core at idle.

If you are starting up with a 32-bit kernel, your best bet might be to use 32-bit Windows in a VM. If you really need 64-bit for some reason, stick with dual booting.