It sounds like something wrong with your Linux. k9copy runs very fast on my laptop. backup a DVD would take me about 40min and that's with 20 - 30% CPU usage (couldn't remember memory usage, but it is pretty low). I have 4G RAM and a mid-low performance CPU (Core2 Duo T5870) in today's market term.
Only couple of things I could think of.
1. Do you have any issue playing DVD on your computer? I read sometimes DMA mode is not enabled for your dvd drive, and playback (or anything else) will be very slow. I trust you can google this.
2. have you monitored your system resource usage?
The difference between genius and stupidity is that genius has its limits.
-- Albert Einstein