calmstateofmind :
If you notice, that's showing information for Core #0, not both combined. On the lower right you'll also notice where it says, "Cores: 2".
So, 1199.9 x 2 = 2,399.8 = ~2.4GHz.
This is incorrect. The CPU is a dual core and both cores run at a maximum of 2.5GHz when under load. But when the CPU is idle, Speedstep is active and lowers the speed to its lowest possible based on the multiplier, for which yours is 6x. The maximum multiplier yours can do is 12.5x which at a 200MHz FSB would be 2.5GHz per core.
http://ark.intel.com/products/37212/Intel-Pentium-Processor-E5200-(2M-Cache-2_50-GHz-800-MHz-FSB)
Per Intels site. And yes you do have Speedstep. Speedstep has been in every Intel CPU since Core 2 was launched and your Pentium DC E5200 is based on the 45nm Core 2 processor architecture.
If you want to see your CPU running at 2.5GHz, run Prime 95 with CPUZ open and it will jump to 2.5GHz. Then turn off Prime95 and it will drop back down to 1.2GHz.