We switched to 2008 in almost a year ago. Mostly with our drawings the speed is comparable. But with some drawings from our clients there is a big difference in speed. A few drawings for that client take up to 5 minutes to open. We were working on one last week that takes about 2 minutes to open. We had a problem with one of the xref components and the drawing would not open at all, even though one of the drawing components would open. I tried everything I could think of to make the drawing work, finally decided to experiment with that drawing in 2006. I converted all of the xref components to 2006, and tried to open the drawing in 2006. It opened in 1 second! From 2 minutes to 1 second is a big difference in speed! Opened the 2006 drawing in 2008, and it was back to 2 minutes.