After I installed 3.8 the other day I noticed that heavy disk activity (like an md5sum on a large file) would use up all available CPU dragging the system to its knees.

While exploring knoppix menus I found an option to enable DMA. DMA does direct transfers from memory to harddisk without using up CPU. It makes an enormous difference in system performance. The md5sum that was taking 5 mins and making the machine unusable for the duration now takes 30 secs and you can't tell it's running. Anybody know why DMA isn't enabled by default and how to make that setting permanent?

Thanks for any info.

dd