I have relativity old Macbook Air with 1.6 GHz Intel Core 2 Duo and 2GB 667 MHz DDR2 SDRAM. Recently upgraded to Lion 10.7.4 and Xcode 4.3.3. Not %100 sure, but empirical evidence seems to demonstrate that when I start using Xcode my OS gets so slow it becomes unusable i.e. the refresh rate is so bad I can see keyframes of the cursor moving across the screen.
I have done the Disk Utility repair thing to no avail (not that I thought it would help anyway). Any ideas of how to cure this ailment?
EDIT
Just was looking at memory upgrade options. Does the below image mean i don’t have any?

2 Gb and 2 cores are barely sufficient to run Lion at all, much less do any reasonably intensive development work.