the n270 is a 1.6ghz cpu, i am writing this from a n455, a 1.66ghz cpu with the same ram
all perfect with kde4
i use it everywhere, i connect external monitors, projectors, speakers, usb flash drives, external hard disks, external dvd burners, all i can think of and everything works very well
have been using it since september last year, nothing big to report, be sure to use the latest kernel
it accepts perfectly compiz and 3d is decent, flash is acceptable with the latest xorg update on most pages
the biggest difference between those two systems is the video card, yours is older than mine, i have a gma 3150 but yours is a gma 945
you have to test how it performs with the livecd, probably will work well