My PC has a quad-core CPU with hyperthreading. Which means that Windows 
claims it has 8 cores, and when I run POV-Ray, it claims to be using 
12.5% CPU.

Right now, I have 4 copies of POV-Ray running, each working on a 
different task. Each copy is using 12.5% CPU, and Windows reports a 
total of 50% CPU usage. (In spite of the fact that I'm actually using 
ALL the cores available.)

I wanted to get a quick preview of the animation being built, so I fired 
up Virtual Dub. Imagine my surprise when I actually got 62.5% CPU! o_O 
Somehow, each core is running a compute-bound task, and yet still had 
enough spare cycles to run a /second/ compute-bound task in the 
background as well!

(Also slightly unusual is seeing Virtual Dub actually compute-bound. 
Usually it's I/O-bound. But in this case - decoding PNG and encoding 
H.264 at 1280x720 - it seems to have become compute-bound.)

The only explanation I can come up with is that POV-Ray is using almost 
exclusively floating-point arithmetic, while Virtual Dub is using almost 
exclusively integer arithmetic. (Can you *do* a discrete cosine 
transform in integer arithmetic alone? I didn't though you could...)

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