What is the difference between PIO and DMA Mode?
PIO and DMA refer to the method used to transfer data between the hard drive and RAM. PIO (Programmable Input/Output) data transfers use the CPU to control data transfers between the hard drive and RAM. DMA (Direct Memory Access) transfers do not involve the CPU, transferring data directly between the hard drive and RAM. DMA modes are thus better for use with preemptive multitasking operating systems such as Windows NT, 2000, XP and Windows 95, 98, 98SE and ME. Transfer Mode Max Transfer Rate Standard PIO Mode 0 3.33 MB/s ATA PIO Mode 1 5.22 MB/s ATA PIO Mode 2 8.33 MB/s ATA PIO Mode 3 11.1 MB/s ATA-2 PIO Mode 4 16.7 MB/s ATA-3 DMA Single Word Mode 2.11 MB/s ATA DMA Single Word Mode 1 4.22 MB/s ATA DMA Single Word Mode 2 8.33 MB/s ATA DMA Multiple Word Mode 0 4.17 MB/s ATA DMA Multiple Word Mode 1 13.3 MB/s ATA-2 DMA Multiple Word Mode 2 16.7 MB/s ATA-3 Ultra DMA Mode 0 16.7 MB/s ATA-4 Ultra DMA Mode 1 25 MB/s ATA-4 Ultra DMA Mode 2 33.3 MB/s ATA-4, Ultra AT Ultra DMA Mode 3 44.4 MB/s
PIO is just very slow and uses a lot of CPU resources. But it should still burn with the same quality as DMA. Just for your information, Windows will automatically revert a ATA channel to PIO when the drive has 6 consecutive read failures. It’s a questionable Windows ‘feature’ to allow the drive to keep functioning. Unfortunately, it won’t reset automatically or let you know that it is in PIO mode. Just be aware if you have a lot of problems reading a disc and then your drive slows down, you need to check to see if it’s reverted to PIO mode. Most DVD burners and DVD ROMs should be DMA 2-4. ROMS are usually DMA 2. Hard drives are usually DMA 4 -6. You should have no drives on your computer in PIO mode. If you can’t reset it with a reinstall of the channel, then you would need to make some registry changes. This involves some risk, so not something you want to do unless necessary.
