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I'm downloading a php editor/platform by Zend called Eclipse. I use a Mac version 10.6.6.

The options for a Mac OS 32 bit or a 64 bit (see image). Does it make a difference which I use? What should I take?

from eclipse

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migrated from Mar 28 '11 at 0:59

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It depends on what computer you're using. If you're using a Mac with a 32-bit processor, then you can only use the 32-bit version.

If you're using a Mac with a 64-bit processor, you can use either. There are two main differences; the 32-bit version will run slightly (possibly un-noticeably) slower, but will be more backwards compatible. The 64-bit version will run slightly (again, possible you won't be able to notice) faster, but there's a possibility you will run into a compatibility issue.

I would probably go with the 64-bit version.

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All recent Macs run in 64bit mode and emulate 32. You can't miss.

That being said. Download the 64bit version.

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32-bit is not "emulated", it's another fully native mode the CPUs can run in. – Gordon Davisson Apr 5 '11 at 4:29

You should go with the 64 bit version. If you're running a Mac that can run 10.6.6, it is very likely that you have a 64 bit processor and you will be able to run 64 bit applications, like the one you want to download.

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I am pretty sure that 10.6 will run on the few, initial Intel Mac models that were 32 bit–only (the very early MacBook, MacBook Pro, Mac mini, and iMac that used “Core Solo” or “Core Duo” processes which only run 32 bit OS and applications). See SU question Snow Leopard on Core Duo. – Chris Johnsen Mar 28 '11 at 2:59

A way to find out is to open terminal, you can do this by typing terminal into spotlight:


uname -a

and it should return a string about your systems kernel, look for either i386 or x86_64

if it shows i386 then your kernel is running in 32 bit mode and x86_64 is 64 bit mode.

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That will tell you what the kernel is running, but it has no bearing on whether the kernel can run 64 bit apps (the “bit widths” of the kernel and application are independent in Mac OS X). – Chris Johnsen Mar 29 '11 at 1:12
Oh right ok, never 100% knew that, given that mine is i386 and still can run 64 bit apps so I get you. – Sandeep Bansal Mar 29 '11 at 13:03

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