Regarding your sluggishness, you can fix that by giving bitcoin a lower priority (it won't slow down generation normally, just means if you want to use the computer for something else that'll get priority) by a command like:
renice -n 15 $(pidof bitcoin)
I'm sure there's a GUI option for it as well somewhere.
Thanks. At the end I minimized bitcoin in the tray icon bar and the sluginesh disapeared. Now bitcoin its taking over the cpu (all the cores running at near 100%) but the machine works fine.
Also make sure your cpu fans are working, your heatsink is actually on, machine is clear of dust, etc or you might overheat.
Thanks. The computer is running my Mythtv server and my torrents 24h so it would have broke alredy if it was in bad state. Also, the Atom 330 does not have a fan. Thre is a fan in the system but it is for the chipset. Curiously enough, Intel did not have time to optimize the chipset as much as the cpu, so the cpu is fanless but the chipset is not, unlike any normal computer system. The next Atom generation is coming or was released shortly and I believe they have integrated the cpu+gpu+memory management (and maybe other stuff) in one chip and the chipset part is small, so it will probably wont require fan. I am not sure if the cpu now requires fan, but if it does not its perfect for a home server. I was previously running a VIA chipset and I dont like Intel too much, but the Atom's are the best at their thing: Low power, low cost and best performance for those characteristics. The atom 330 even runs 720p video without problems (it can not handle 1080p).