I happily run Linux (Kubuntu 8.04) on what I'd define a "rather powerful laptop".
I mean, "Intel(R) Core(TM)2 Duo CPU T7500 @ 2.20GHz", 2 GB RAM, SATA HD etc.
In a number of cases the system becomes unresponsive (or very slowly responsive) to keyboard/mouse interaction.
I'm not using any 3D desktop, though.
In my mind I should be able to rise the responsiveness somehow, but don't know how.
In my mind, there'd be plenty of computing resources to do it without even harming the CPU/RAM/I-O intensive tasks.
If a DVD burning took 15 minutes instead of 10 while I'm using my (responsive) text editor, I would say the system is performing great with two tasks at once.
If my WAV->OGG encoding took 6 minutes instead of 5 while I browse a PDF manual, I would say that the system is productive to me, in the sense it can do things in the background of my main job.
What happens, instead, is that highly intensive tasks make the system unresponsive thus bringing in the foreground those tasks that I expect to run in the background.
Any hint on how to reverse such a behaviour?