Why does my new 2.4GHz 15" MBP feel much more sluggish than my nearly 3 year old 2.16Ghz 20" iMac? It's got way more powerful video hardware (and way larger amount of video memory). It has a faster processor. It has a faster FSB with DDR3 instead of DDR2. The only thing my iMac has over my MBP is 3GB ram (2x2GB pair, but the generation of chipset is only able to use 3GB) as opposed to 2GB and possibly a faster hd (both are the ones they came with, but my MBP is 5400rpm and maybe the iMac's is 7200rpm). They even have the same size hds. Could 1 GB ram really be making all this difference? Could having a 5400rpm hd rather than 7200 rpm be the explanation? I was expecting my new Mac to be noticably FASTER than my old one, not SLOWER. They're both running Leopard, by the way, and the MBP feels faster when in Windows in the same manner that it feels faster in OS X.