Hmm, I am using 64MB of compressed swap for the last several months and that, combined with second swap on microsd (and 805 MHz OC) makes my n900 responsive and fast for normal usage - the only times I see lag and stutter is when the device reconnects from GPRS to WIFI and back, but I assume that normal, after all I have 4 IM + 3 email accounts and everyone fights for CPU/IO bandwidth on such reconnect.