Rafael Garcia-Suarez shares a helpful tip to correctly enable APM in his D420 running Ubuntu, but I can confirm that my D620 behaves the same -ignoring APM level 255 and disabling APM completely instead- and that his fix runs equally well, just by adding
/dev/sda {
apm = 254
}
to /etc/hdparm.conf and making sure that /etc/init.d/hdparm runs at startup (the default after apt-get installing hdparm in my case).
The laptop is cool. I purchase a new from dell. However, The battery of running time is too low. I bought new one from http://www.batterygoshop.co.uk/dell/latitude-d620-battery.htm . Does anyone have this problem?