cpu - Any way to check the clock speed of my processor?

Is there any way to check at which clock speed my processor is running?

I have already tried cat /proc/cpuinfo but the clock speed I'm running isn't showing. I know Ubuntu 12.04 (Precise Pangolin) requires 700 MHz and VGA, but will an AMD Mobile Sempron work?

From the command line type lscpu. The information will be at CPU MHz:

~$ lscpu | grep MHz

CPU MHz:               804.901
CPU max MHz:           3200.0000
CPU min MHz:           800.0000