Back in February, I wrote about the performance I was seeing with my Mac Pro, and compared it to several other machines. My intent was to compare performance between various different machines and configurations…but it had the unexpected side effect of giving me a baseline with which to measure new versions of Adobe Photoshop Lightroom.

This data proved to be quite useful when Lightroom 2.0 was released, and I could test the 32-bit build against the 64-bit build. What I found was surprising.

Just like last time, the basic test was generating 1:1 previews for 211 raw images (compressed NEF format from a Nikon D200), about 1.75GB of files.

First, Lightroom 2.0 32-bit:

Mac Pro, 2 x 2.8 GHz Xeon, 8 cores, 12GB RAM, OS X 10.5.5
CPU utilization between 350-500% throughout
Total time 4:57, average 1.41 sec/image

And Lightroom 2.0 64-bit:

Mac Pro, 2 x 2.8 GHz Xeon, 8 cores, 12GB RAM, OS X 10.5.5
CPU utilization between 500-550% throughout
Total time 7:06, average 2.02 sec/image

So the 32-bit version on OS X 10.5.5 was actually a bit faster than my previous tests of Lightroom 1.3.1 on 10.5.2, which could be due to either the Lightroom 2.0 upgrade, or 10.5.5 changes.

But the 64-bit version of Lightroom 2.0 totally blew chunks, as you can see. Pretty disappointing, and totally reproducible for me, so I opened a ticket with Adobe. They got back to me saying they could reproduce the problem, and also had a bunch of mumbo-jumbo about how there is more overhead in accessing memory in 64-bit mode (which I’m not sure I believe, but I’m not up to speed enough on the Leopard 64-bit implementation to know for sure).

Well, Lightroom 2.1 was recently released, and here is the data:

Lightroom 2.1 32-bit:

Mac Pro, 2 x 2.8 GHz Xeon, 8 cores, 12GB RAM, OS X 10.5.5
CPU utilization between 350-500% throughout
Total time 4:55, average 1.40 sec/image

Lightroom 2.1 64-bit:

Mac Pro, 2 x 2.8 GHz Xeon, 8 cores, 12GB RAM, OS X 10.5.5
CPU utilization about 400% throughout
Total time 4:05, average 1.16 sec/image

Wow – obviously a big change; the 64-bit version now totally rocks. There was something in the 2.1 release notes about enabling SSE extensions in 64-bit mode – sounds like that might have been the bug!

I didn’t record the memory usage numbers, unfortunately…but I remember watching during the runs, and the 64-bit version seemed to be using about twice the memory that the 32-bit version did.