Do you see anything when you look under /sys/devices/system/cpu/?
$ sudo cat /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_max_freq
2667000
Also you could try this. Install "cpufrequtils" package, you can change your governor and frequency using:
$ cpufreq-set
Current governor and frequency could be found using the command:
$ cpufreq-info
References
The words “CPU”, “processor” and “core” are used in somewhat confusing ways. They refer to the processor architecture. A core is the smallest independent unit that implements a general-purpose processor; a processor is an assemblage of cores (on some ARM systems, a processor is an assemblage of clusters which themselves are assemblages of cores). A chip can contain one or more processors (x86 chips contain a single processor, in this sense of the word processor).
Hyperthreading means that some parts of a core are duplicated. A core with hyperthreading is sometimes presented as an assemblage of two “virtual cores” — meaning not that each core is virtual, but that the plural is virtual because these are not actually separate cores and they will sometimes have to wait while the other core is making use of a shared part.
As far as software is concerned, there is only one concept that's useful almost everywhere: the notion of parallel threads of execution. So in most software manuals, the terms CPU and processor are used to mean any one piece of hardware that executes program code. In hardware terms, this means one core, or one virtual core with hyperthreading.
Thus top shows you 4 CPUs, because you can have 4 threads executing at the same time. /proc/cpuinfo has 4 entries, one for each CPU (in that sense). The processor numbers (which are the number of the cpuNUMBER entries in /sys/devices/system/cpu) correspond to these 4 threads.
/proc/cpuinfo is one of the few places where you get information about what hardware implements these threads of execution:
physical id : 0
siblings : 4
core id : 0
cpu cores : 2
means that cpu0 is one of 4 threads inside physical component (processor) number 0, and that's in core 0 among 2 in this processor.
Best Answer
From the T520's specs:
The i5-2520M has 2 cores + hyper threading, for a total of 4 cores seen by the system.