Sluggish Browser window in 4.5?

I'm a long time Capture One user and am looking at the new 4.5 and 4.5 Pro versions and am noticing a SIGNIFICANT slowdown in the speed at which I can browse from image to image in 4.5 versus 4.1.2. I would like to move up to the Capture One Pro 4.5 version just to get the customizable tabs as it would considerably speed up my workflow to have all of the tools I use in one tab. However, I'm a collegiate sports photographer and need to select from hundreds to thousands of images of each event and any workflow speed increases are more than offset by the nearly one second delay when moving from one image to the next. Capture One's big strength for me was the speed at which I could edit, adjust, and process large numbers of images but the sluggish browser window severely impacts that speed. I'm running on 2.6GHZ Mac Pro under Mac OS X 10.5.5. Any suggestions or help would be greatly appreciated.

Jeff Huehn

P.S. - Bring back sort by ISO !!!
P.P.S. - and sort by processed status!