i installed cpufrequtils and attempted to set the max to 2.4, but it appears to be in bios controlled mode so that has no effect.

I gave up for a bit and closed the lid, then checked with cpufreq-info and suddenly the range is 500-2.5ghz.

seems to be fairly reproducible:

1) boot cold

2) run cpufreq-info (expected range 500-800mhz)

3) close lid for > 20seconds

4) open lid, log in, run cpufreq-info (expected range 500-24.ghz)

this is confirmed with the stats in powertop as well.

15.04 has a 'proprietary microcode' driver under Software & Updates in settings. Seems to correct speedstep behavior (as well as the trackpad issues--although i think the latter is just the newer kernel).

I have the same issue.

- Boot PC unplugged: Works at 500-700MHz
- Boot PC plugged: Works at 700MHz-2.2GHz (if I unplug it later, it stills at this range)

- Disable SpeedStep on BIOS gets CPU always working at 2.2GHz.

I tried a lot of things with cpufreq, and the only one that "works" for me was enabling ignore_ppc flag and set again the frequency policy. But I don't like to disable este flag...

Somebody found some good solution?

install 15.04 it works fine after that.

I noticed a lot of visual choppiness at Factory Defaults.  I upgraded my kernel in place (14.04 running 3.19.0-18 now) and it resolved it for me.  I attributed it to the newer chipset having drivers in the newer kernel.

My only concern with disabling SpeedStep would be diminished battery life which is why I went with the 13 and not the Precision M3800.

Edit: Here is a link to the thread I made about how to upgrade your kernel to 3.19 using the early preview kernel repository for LTS Enablement:

http://en.community.dell.com/techcenter/os-applications/f/4613/t/19632562

If you cannot connect to ethernet via hardline/mobile hotspot, read down the thread a ways...there is a different upgrade path that should keep wifi working throughout.