How to determine if a new Mac Pro defaults to 64 bit OS?

Hello all wise ones

I've been waiting to buy a new mac until one came out that boots into a 64 bit environment by default.

It is my understanding that certain new macs do just that.

Does anyone know what to type into the terminal that will tell you whether Snow Leopard is running under 32 or 64 bit?

What is the value of 64 bit?

I don't know, but it sounds cool, and besides I'll be ready if something 64 bit ish develops with any of my most used apps

thanks for any info

rockin ron

Sigh. Hardly a week goes by that I don't run into somebody who's deeply confused about this one.

Four points:

1. The 2010 Mac Pros boot a 64-bit kernel by default.

2. All currently shipping Macs are 64-bit systems, and have been for some years.

3. All currently shipping Macs run Snow Leopard, which is a "64-bit environment," to the extent that that phrase even means anything.

4. The only, and I mean only difference between the 32-bit and the 64-bit kernel in Snow Leopard is that you have to run a 64-bit kernel to address more than 32 gigabytes of RAM in the kernel. You can cram 96 gigs of RAM into your Mac if you want and it'll run just fine, but things like filesystem caches will only consume a maximum of 32 gigabytes of that RAM. Your actual applications, assuming they're 64-bit some are and others will be sooner or later, have full access to more RAM than you could ever afford, and all the 64-bit high-performance low-level stuff the Core 2, i-series and Xeon processors offer. You will see absolutely no difference between a 32-bit and a 64-bit kernel at the application level.

There's a ton of really crappy information out there about 64-bit computing and 64-bit kernels in Mac OS X. There's one site in particular ? to which I will not link here ? that claims to have measured a thirty percent application performance boost when booting a 64-bit kernel, which is a pure physical impossibility. It seems like the Google search results are dominated by enthusiastic kids who have only a cursory understanding, if any at all, of the architecture of the Mac OS X operating system or the implementation details of Intel's 64-bit microprocessors. So do not believe everything you read.

Short version: You really, really don't care about this. Make your purchasing decision based on factors that actually affect you.

Here is a handy list of those that boot into 64-bit by default (just Xserves and 2010 Mac Pros):
[support.apple.com]

Here is how to set it to boot into 64-bit mode by default:
[support.apple.com]

The advantage of a 64-bit kernel is that it can address more memory, has lower overheads if you have a lot of RAM, it offers performance advantages, etc. However, you will need to make sure that all device drivers and third-party kernel extensions are compatible, as this can cause problems. That is why it is not switched on by default for consumer systems.

Also, be aware that you do not need to boot into 64-bit mode to run 64-bit apps.

My software:
Pro Maintenance Tools - Tools to keep Final Cut Studio, Final Cut Pro X, Avid Media Composer and Adobe Premiere Pro running smoothly and fix problems when they arise
Pro Media Tools - Edit QuickTime chapters and metadata, detect gamma shifts, edit markers, watch renders and more
More tools...

Hey Jeff, did you run into any problems running FCServer on 64 bit? We've had lots of trouble with it and found that making it run in 32 bit stopped the trauma.

Oh, wait, possibly it's because the computer trying to access it isn't compatible. That makes perfect sense now..It's a pre 2010 MAc mini that's giving us the trouble, I think.

Nope. Final Cut Server includes no kernel pieces at all; it doesn't know or care what ABI the kernel uses.

What kinds of trauma did you have?

It just wouldn't open on the Mac Mini, until we did a get info and changed it to 32. Also, for some reason it kept defaulting to the wrong address, which was also resolved. *shrug* Works now.