Why do ultrabooks have lower Ghz CPU speed?

eldapeeze

Honorable
Dec 23, 2012
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10,510
I've noticed with desktops and older PC's you could get a CPU with 3.30 ghz or higher. Yet I've looked at ultrabooks and noticed even the good ones don't give you anything higher than 1.70 Ghz. What's the reason for this? Thanks.
 

nukemaster

Distinguished
Moderator
Ultrabooks are about thin and light. Higher clock speed cpus generally run hotter and take more power. These more powerful cpus drain batteries faster and require a thicker heatsink.

If software can use all the cpu cores, this lower speed is less of an issue.

Also note that clock speed is not always an indicator of performance. Look at how the 2.4 GHz Core 2 duo cpus killed 3.8 GHz P4s(including the dual core ones).

Intels current cpus have a trick too. when running a program that only uses one core, the others can enter a low power state and allow the single core to clock up to a higher speed(Turbo).
 

eldapeeze

Honorable
Dec 23, 2012
7
0
10,510
So I'm assuming these low end CPU's in Ultrabooks can still perform well? Like there won't be a drop in processing? Or does it depend on what you're using it for? So if I were to do video editing or high end gaming on an ultrabook, would I have to have a faster CPU or something?