Difference between /proc/cpuinfo and /sys/.../cpuinfo_cur_freq

[Dirk Gfroerer <Dirk Gfroerer guh-software de>]

I've got a Pentium D processor with 3 GHz (i.e. a Pentium D 830). 
According to Intels specification the processor supports SpeedStep. 
cpuspeed is running and according to 
/sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies the 
processor can switch between 2.8 GHz and 3 GHz.

If I query /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_cur_freq it is 
telling me most of the time the processor is running at 2.8 GHz. Nothing 
is wrong with this. However /proc/cpuinfo still tells me the processor 
is running at 3 GHz? According to the recent discussion on this list 
about an Opteron 875 showing up only with 1 GHz and my experience with 
notebooks I'd expect /proc/cpuinfo and /sys/.../cpuinfo_cur_freq to be 
in sync.

Is this something I should worry about (i.e. open a support ticket / 
bugzilla entry) or is it working as designed?

The kernel running is 2.6.9-22.ELsmp (i686); i.e. U2 with all updates.

Thanks,
Kind Regards,
Dirk