I noticed when I installed the update to 6.5 on my Mac Pro, the average time per image to process went up from about 15 seconds to about 22 seconds. Of course, DXO is currently doing an even better job of rendering the RAW images from my Canon 20D. The end result looks better (especially in the background in pictures that include shadow detail- there's a great deal less of the "threadbare rug" effect and the areas that have little or no illumination or detail present).
I have 7 GB of RAM installed and my Mac Pro is the original model from 2006 so it doesn't have all the bells and whistles of the newer ones. I did some checking in the DXO Preference window and found that the new version of the software had GPU Acceleration checked but that the Batch processing power slider was set to the middle between Minimum and Maximum. I slid it over to "Maximum" and when I processed a batch of 76 images that I took yesterday it began to serve up the finished jpg images at a rate of 4 at a time (I have 4 cores on the Mac Pro) instead of 2 at a time which I had been getting ever since upgrading to version 6 (I hadn't bothered to change or even check on the performance settings since I had always averaged about 15 seconds per photo I didn't worry too much about going from 2 at a time to 4 at a time. Checking the Activity Monitor I could see a lot of activity in the 4 cores regardless of whether it is turning out 2 or 4 finished jpegs at a time).
Anyway, the 6.5 was slower than before in output with the slider still set between the extremes- but when I re-set it to "maximum"
the 76 jpegs were produced in a total of 1247 seconds - an overall average of 16.41 seconds per jpeg but since is was producing 4 per cycle the actual processing time for each RAW file to Jpeg was just over 65 seconds.
DXO does such a spectacular job for me that I wouldn't care if it took 5 minutes per file. With batch processing I can just set running and forget about it till it's done. Any last minute touchups can be done in Aperture where I can pump up the brightness, sharpness etc. and get rid of blemishes and almost never have the need to open my copy of Photoshop CS3 which is always a pain to use.
You didn't mention the size of your RAW files. My old 20D is only 8 megapixels and puts out 7 to 8 MB RAW files. If you have a new camera with much larger RAW files I'm sure that you could expect the processing time to increase.
pictures from our recent snowstorm in the Twin Cities, these were all taken with my Canon 20D, a Canon 17-40L lens, and a polarizer
processed as 90% jpegs (the default that DXO chooses initially) and the jpegs were tweaked in Aperture 3.1 (almost entirely consisting of the use of the "Straighten" box to get the pictures level:http://picasaweb.google.com/jamesn88888/TheGreatSnowfallOfDecember11#