Which version of Eclipse should I run on OSX? 32bit or 64bit?

Question

This may be a silly question but should I use the 32 bit or 64 bit version of Eclipse on my Mac?

I'm fully up to date with Snow Leopard and all patches and I have a pretty recent iMac (30", Dual Core, 3GB)

I thought that Java on Snow Leopard was now 64 bit only so can't understand why there is a 32bit download. Is it just the Eclipse download page that is showing 32 bit for older versions of OSX?

Superior

Answer 1

You're probably better off with the 64-bit edition. Nearly all the system software is 64-bit in Snow Leopard, and if you only run 64-bit apps, you don't pay the cost of having to load the 32-bit runtimes (which can consume quite a lot of memory). It may also benefit from the 64-bit memory model, though I'm not sure how well the JVM takes advantage of that yet. I expect the 32-bit version is provided for Leopard (and earlier) compatability.

Corcyra

It is possible to use Java6 in 32 bit mode in Snow Leopard. Just use the -d32 switch to start it. It is seldom needed, but sometimes useful, as 32 applications use a bit less memory. – Borak

Does eclipse in 32bit mode use less memory than in 64bit mode? Given that Java has fixed memory limits, I don't see huge benefits to having it run in 64 bit mode. – Fairish

I don't know off hand; it depends on several factors. The JRE itself may technically use less memory in 32-bit mode (simply due to the word size and alignment) but as mentioned above, if it is the only process requiring the 32-bit runtimes (CoreFoundation, Cocoa, etc, etc) then overall it could actually be consuming more memory than the 64-bit edition (which will use the runtimes already loaded by the system). – Corcyra

64bit JVMs often use compressed references, in which case references still take 4 bytes. #6906094 – Raptorial

Answer 2

I would use 64bit Eclipse.

Gossett

Answer 3

safe bit is 32-bit :)

Colitis