cpu frequency problem

[Victor Sterpu]

I use Ubuntu 8
I have a acer travelmate 5720 dual core 2.2Gh Intel.
When I do cat /proc/cpuinfo I se this:
...
model name    : Intel(R) Core(TM)2 Duo CPU     T7500  @ 2.20GHz
stepping    : 11
cpu MHz        : 800.000
...

I did a test with lmbench and the cpu frequency is reported as
[MHZ: 2378 MHz, 0.4205 nanosec clock]

What is the correct frequency?
Why this 2 values do not fit?

Thank you.