Pentium III 500MHz is a fast processor for many things. I have only 512MB in this Pentium 4 2400MHz machine and four 8x and one 4x DVD writers are connected here, in addition to a few hard disk drives.
DVD writing at 1x to 8x depends more on IDE/ATA devices than CPU clock speed. If the board has good IDE controller for DVD writers, there should not be any problem.
Some notebooks automatically sets the CPU speed from 1.5GHz to 500MHz to save battery for longer use. DVD writing is still possbile at the reduced speed.
If you already have a DVD-ROM drive and a HDD, test the drive’s read and write speeds. Simple file copy and move can do. The peak speed for 8x DVD writing is about 11MB/s. Common requirement is 2x the maxium writing speed so minimum sustained transfer rate (read speed) of source drive for 8x DVD writing is about 22MB/s. Everyday computer usage involves heavy file fragmentation and 10-90% CPU usage, so more processor power and more HDDs always help. Low-powered system can limit drive’s writing speeds.
Additional ATA and SCSI controllers are useful in providing extra bandwidth. Both are available for as little as about US$10 per card.