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Enabling 64-Bit in Snow Leopard

August 28th, 2009 Leave a comment Go to comments

The most powerful update in Snow Leopard is the ability to move to 64-bit support.  By default, Snow Leopard has 32-bit enabled and you have to purposefully enable 64-bit.

Here is how to determine if you have 64-bit enabled.

  1. Start the Systems Profiler through the Applications or Click the on the Apple Menu and choose About This Mac > More Info
  2. Highlight “Software”
  3. Look to see if the “64-bit Kernel and Extensions” has a Yes or a No to identify whether 64-bit is enabled.

64bitOFF

Enable: To enable 64-bit you have to hold down the 4 and 6 on the keyboard when you boot up the computer. Check back in the Systems Profiler and it should be marked as yes.

I am not sure if they will turn this into an official setting some place, but here is how to enable 64-bit by default on startup. Huge thanks to netkas.org who originally posted these settings.

Long Term Enable:

Find this file…

/Library/Preferences/SystemConfiguration/com.apple.Boot.plist

In that file, find the lines that read:

<key>Kernel Flags</key>
<string></string>

and change them to

<key>Kernel Flags</key>
<string>arch=x86_64</string>

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