Xcode 4 runs horrifically poorly on new i5 MBP.

So...I have a major issue, I'm taking a iOS Development course and have hit a really big issue. You see my updated copy of XCode 4 runs very poorly, I'm talking about it using >4Gb of Ram (Just on XCode! I'm swapping over 2Gb!) on my 2011 13' i5 MBP. This has become a major issue, work is nearly impossible. Now here is where things get weird. The iMacs in class have 2Gb of ram and Snow Leopard and work just fine, no memory leak at all...Help!

EDIT: with my Dev account I got myself a copy of Lion and Xcode beta, the problem is gone. (I'm loving this BTW, The trackpad is way more useful, I'm using it more than my mouse!)