applications designed to take advantage of multi-core

question:

i have a copy of sony vegas movie studio 6, which was released late 2005. when i bought it, i believe intel was just taking the wraps off their first quad-core desktop cpu (correct me if i'm wrong). but at the time of this program's release, single core systems were still plentiful, although dual core systems were making in-roads too.

the point i'm getting to is this: i have vegas installed in windows 7 (don't need to upgrade vegas as i'm still using a standard def camcorder) and when i render a movie, i notice that all of my cores get a workout--sometimes 100% on all cores. i'm not complaining about the usage, i'm just surprised that a program that was written before quad core cpus were plentiful can acutally make use of all of the cores. how is that so? in comparison, i have programs that were written 2008, 2009 that only (mainly) use one core out of the four--so how does a program from 2005/06 make use of all cores?

curious...

Multi-threading has been around for quite awhile. If the application and data are so structured that one thread doesn't have to wait on results from another thread, the OS scheduler will assign the threads to the available resources(the cores.)

If you want to see another app that gets flat out 100% core usage almost 100% of the time during video encoding look at FAVC. He splits the video into 4 pieces for a quad core and runs one copy of the video encoder for each slice. Then the pieces are all reassembled into the video stream.

If you have to wait for the result of one operation on some data to proceed to the next step, then you have high idle processing time.