hi levent d,
i only tested on my 2.2Ghz machine so i assumed that was the baseline, what i would suggest is lowering num from 440 to say 200,i.e. decrease the resolution a little. the point was to get a simple working implementation. To get a 'fast' mandelbrot generator you need to use a compiled language, some programs can be found on wikipedia's page- e.g. quickman.
09 Mar 2007
It does not work normally @ p-III 800 Mhz, 256 MB ram
21 Dec 2006
Alfonso F R
It takes around 3 minutes to render on the pentium III i tested on (just executing 'mandelbrot'-no arguments).
When zooming in you see a lot of white space.
When zooming back out, you don't see the full set, but around 80% of it.
Anyway, good work and thank you for posting!