Have you installed your computer's chipset and HDD controller (E.g SATA) drivers?
I know that Windows usually does that for you, but it usually installs the drivers that came with it (And they are usually terribly old).
What is the transfer mode for your drives (HDD and your optical drive)? Make sure that DMA is being used (PIO WILL mean trouble).
To check the transfer rates, right-click on your IDE/SATA controllers in the device manager and click on "properties". The transfer mode should be displayed on one of the tabs.
Not all controller drivers will show the data transfer rate, so do not be alarmed if you cannot find it.
Try to update your drive's and computer's firmwares too.
Disabling any anti-virus software before you burn your discs might help too.
SCPH-10000 S. MINOKAMO v1.01 (Defunct)
SCPH-10000 S. KISARAZU v1.00 (faulty)
SCPH-15000 S. KOHDA (With warranty seal!) :D
DESR-5100 S. EMCS