CPU Usage

[simontarr]

Hi All,

I have a Core 1 Duo iMac 2GHz, and have a quick question about the CPU usage. Because I have two cores, should the CPU usage read a figure out of 200% or does it combine the two cores into 100%?

The reason I ask is that even on really CPU-Intensive tasks, like HandBrake, it will hover on about 87% (In Activity Monitor and iStat Pro Widget) but every so often, I notice go above 100% (sometimes it reaches 157%, before going back down again) Is this because the application isn't 'dual-core' optimised?

I would like to know because it seems like I'm only ever using 1 core.

Thanks for you help guys/gals.

 

[bousozoku]

You can use the CPU usage window in Activity Monitor to graphically show you an estimate of what each processor or core is doing.

Did you see this thread?

 

[robbieduncan]

200% would be both cores working flat out. 100% is one core working flat out (or not, could be both cores working 50%). A single-threaded app can never use more than 100% of the CPU. A multi-threaded app can use more than 100%...