I installed recently Kubuntu 11.10 32 bits (had graphics driver issues, wanted to try on 32 bits version) on my new Alienware M17x, with a Core i7-2670QM CPU. Cores are supposed to be clocked at 2.2 GHz, however the output of

$ cat /proc/cpuinfo | grep -i "hz"

gives me:

model name      : Intel(R) Core(TM) i7-2670QM CPU @ 2.20GHz
cpu MHz         : 800.000
model name      : Intel(R) Core(TM) i7-2670QM CPU @ 2.20GHz
cpu MHz         : 800.000
model name      : Intel(R) Core(TM) i7-2670QM CPU @ 2.20GHz
cpu MHz         : 800.000
model name      : Intel(R) Core(TM) i7-2670QM CPU @ 2.20GHz
cpu MHz         : 800.000
model name      : Intel(R) Core(TM) i7-2670QM CPU @ 2.20GHz
cpu MHz         : 800.000
model name      : Intel(R) Core(TM) i7-2670QM CPU @ 2.20GHz
cpu MHz         : 800.000
model name      : Intel(R) Core(TM) i7-2670QM CPU @ 2.20GHz
cpu MHz         : 800.000
model name      : Intel(R) Core(TM) i7-2670QM CPU @ 2.20GHz
cpu MHz         : 800.000

If useful, the AC adapter is plugged in (yet the ouput is the same when the computer is powered only by the battery) and I have Firefox and Eclipse running.

Does /proc/cpuinfo reflect a possible automatic downclock made to save power if processor load is low or is this output abnormal?

EDIT: Ok, I checked and yes, the ouput does vary in function of the load. I reach 2.2 GHz when needed. But my following problem remains.

I was checking my CPU clocking because I experienced poor performances when reading 720p video files on Ubuntu with VLC or mplayer when on battery (and I believe VLC by default only uses CPU, not GPU to decode), whereas I haven't got such problems with VLC on Windows (which made me think it wasn't coming from a BIOS option, plus every option in the BIOS regarding the CPU is turned ON).