Is lightroom faster on MAC OS than windows?

I have LR running on both an iMac and PC. And I must concur that it does run faster on the Apple hardware by a longshot. I don't have any way to quantify this - just speaking from experience. My iMac is an i7 860 w/16GB RAM (OSX Lion) w/7200rpm drive and my PC is an i7-950 w/16GB RAM (Win7-64) w/SSD.

My PC hardware smokes the Apple hardware and LR runs significantly better on the Apple hardware. It becomes more noticeable with the larger D800 NEFs. But both get a bit laggy when the library gets quite large.