phaq

So you finally own one of these newly released Apple MacBook Pro with fancy Core i7 Quad-Core CPU?
Then you fire up your VirtualBox VM and are disappointed about the sloppy performance?

Luckily, it’s only a (hopefully short-lived) compatility issue. While this will surely need a final fix, here’s a temporary workaround…

Apple decided to boot the x86_64 64-bit kernel by default on Mac Pro (mid 2010) and MacBook Pro (early 2011).

Unfortunately there seems to be an issue between VirtualBox and OS X using the 64-bit kernel on the new Sandy-Bridge Systems, which causes poor VirtualBox performance.

If you suspect this to be the case, run “System Profiler”, which you find either through Spotlight or in Apple-Menu -> About this Mac -> More Information. Click the “Software” item and check for the “64-bit Kernel and Extensions”. If it reads “Yes”, you’re running the 64-bit kernel and are likely to be affected by this issue.

To fix the issue for now, set OS X to boot using the 32-bit kernel.
Open a “Terminal” and run this command to do so:


sudo systemsetup -setkernelbootarchitecture i386


If you decide to use the 64-bit kernel at a later point, just revert it using this command:


sudo systemsetup -setkernelbootarchitecture x86_64


Let’s hope, that this issue will get a proper fix soon. Until then, most of will live good enough using the 32-bit kernel, as it will also run perfectly using native 64-bit apps. It shall be noted though, that some apps, e.g. for graphics processing, may suffer a slightly degraded performance using the 32-bit kernel. Personally I’m not using such applications, so it’s fine for me. After all, my VirtualBox VMs run full speed again.

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