Earlier this month, Adobe announced that there would be [three upcoming improvements](http://news.cnet.com/8301-30685_3-57371809-264/adobe-offering-new-reasons-to-get-dng-religion/) to the DNG camera raw "standard" that would improve performance. I've not historically converted my RAW files to DNG, but performance improvements would certainly be a big factor in a decision to move to that workflow. I don't know whether any of the announced improvements have actually made it into Adobe Lightroom 4, but I the upgrade from version 3 to 4 last night ($79), converted some files to DNG, and ran tests. Navigation and editing was as sluggish as ever on my 12-core Mac Pro (with plenty of RAM)—I couldn't tell if there were improvements when working with DNGs. Then, I did some exports to 1920-pixel JPG files:
**Test 1: 28 ARW raw files from Sony NEX-5N** ARW->JPG, 2010 Process: **52 seconds** [ARW/DNG]->JPG, 2010 Process: **40 seconds** DNG export **23% faster**
**Test 2: 28 CR2 raw files from Canon 7D** CR2->JPG, 2012 Process: **62 seconds** [CR2/DNG]->JPG, 2012 Process: **43 seconds** DNG export **30.6% faster**
Here's the CPU graph for the export process. You can see the clear improvement in CPU utilization in the DNG export.
CR2->JPG export (green), DNG->JPG export (orange)
*24 virtual cores in 12-core Mac Pro*
It does seem that there are real reasons to convert raw files to Adobe's DNG raw format. If Adobe continues to improve DNG performance, I'll likely move my workflow over to DNG conversion upon import.
I love Lightroom—it is my photo organization and processing app of choice—but in general, Adobe Lightroom 4 feels sluggish, and it took as many as 6 seconds to move between Library and Develop modes (inconsistent, presumably due to caching). No interface move should take 6 seconds on this computer. I hope there is a performance update in the near future that deals with the poor performance.[^1]
[^1]: To be clear, Adobe Lightroom 3 also feels sluggish.