Update: two readers have reported gluttonous memory usage by LR 3. On reader reports LR3 using 12GB of real memory. Another reports it taking 3.4GB real memory on his laptop. In my recent testing, I did not observe this bug, though I had previously seen runaway memory usage with LR2.
A beta version should be near-final— feature complete, architecturally stable, just minor bugs to fix. So I expect performance of a beta version to equate reasonably closely to the final release, and in that regard the future looks dim for Lightroom 3.
I downloaded Adobe Lightroom 3 and ran a brief test of Import of 128 Canon 21MP CR2 files, running both Lightroom 2.6 and Lightroom 3 as 64-bit applications, and using the Mac OS X Snow Leopard 64-bit kernel (here’s how). I used my quad-core 2.66GHz Mac Pro Nehalem with 12GB memory, and an ultra-fast 4-drive striped RAID capable of 500MB/sec. Memory usage with Lightroom 3 was modest, staying sell under 1GB.
I ran the test twice for each version of Lightroom, rebooting each time and starting with an empty catalog, no cache, etc. The results are plain to see: if you want a major slowdown for Import, Lightroom 3 beta delivers your coffee break to you.
Curiously, while Lightroom 3 makes more use of CPU cores while generating 1:1 previews, utilization is erratic: during an Import, its CPU utilization is near maximum initially, then it plummets to perhaps 200%, and then for a long time it uses 580% on average (max 800% for 8 virtual cores on a quad-core Mac Pro).
But increased CPU usage does not mean increased efficiency. Even as it gobbled CPU resources, Lightroom 3 ran substantially slower than Lightroom 2 for Import, as the graph shows. That could mean a variety of things, perhaps the RAW conversion is different from Lightroom 2 (I used high quality 1:1 previews for both). Or it might just mean poor implementation. Changes to conversion algorithms are always of concern, since that means you can never rely on getting the same results! I don’t know the explanation.
I haven’t yet tried Lightroom 3 Export, but see my Optimizing Lightroom page for a performance tip good for a substantial speedup.
Neither Lightroom 2 nor Lightroom 3 fully utilizes a quad-core Mac Pro for Import, which is one example of why I’ve advocated for some time now that a quad-core machine is as good or better than an 8-core machine for most users, due to the current state of Adobe software, see When More is Less. Specific software (other brands/programs) can use 8 cores, see the list. So the choice depends heavily on where you spend your time (which applications doing what). Even so, when software is updated to utilize all CPU cores better, it’s a big win whether you have a 4 or 8 core Mac Pro, which have 8 / 16 virtual cores respectively ie hyperthreading.
As an aside, the new Lightroom 3 Import dialog is one of the most godawful designs yet foisted on the public, with important settings scattered left/right/top/bottom in the dialog, and a butt-ugly dark gray interface with terrible visual ergonomics. The dialog cannot be resized, so it’s either too small or absurdly huge on my 30" display. Is nonsense like this why Adobe takes so long to improve real features? The Lightroom 2 dialog was clean and well designed, I dread explaining to a newbie friend of mine how to grok the Lightroom 3 mutation.