divx 5 is actually a little more compact so it tends to take less, but it really depends on the encoding settings (eg: bitrate, etc) that were used for the movie.
To give you an example, with a bitrate of 800Kbps, it will obviously require more CPU power than something encoded at 680Kbps. Low-Pass and High-Pass filter settings can also be a big role. With older methods (nandub and such) some people setting the Low-Pass filter to 6000 will cause trouble to those with older PC systems. In general it is better for them to use 4000-5000 for Low-Pass (so that even Pentium 2 users can view without hickups).
Anyhow, before I go off into too deep an explanation, it just simply depends on how the movie was encoded. The better the picture and sound quality of your movie, the more resources it will hog. There is no way of getting around that.
But all the players mentioned work well and you'll just have to make due. I don't know your PC specs, but as long as you can view your movies fine without hickups, don't worry too much about the CPU usage.
Good luck.