It's important to note that the multiplier's halvation is not set in stone. The fact you see your multiplier (and logically your CPU speed) halved is just a power-conserving procedure Intel calls SpeedStep. All it does is monitor if the CPU is actively being used, and if it isn't, it puts the brake on the speed decreasing the power draw.
As soon as SpeedStep notices the CPU is being used again (for example, while gaming or watching movies) it releases the 'brake' again and your CPU gets back to its full multiplier and speed. So it conserves power while not taking away any performance.
There is however one area where SpeedStep can get annoying, and that is OC'ing. SpeedStep usually lowers the multiplier and the voltage as well, but when you run OC'd, your halved clock speed is also higher (you OC by increasing the FSB, while SpeedStep only affects the multiplier). If your Atom chip can't cope at that higher speed with the lower voltage, it will crash. Since there is no option in the BIOS to turn off SpeedStep, you have to use a workaround. This workaround is called the HLT Command, and is a process integrated with RightMark CPU Utility. What the process does is trick your Atom and OS into being 100% loaded (while not being stressed at all), so SpeedStep doesn't get a chance to hit the brakes
Don't make me "touch" you :-D