I purchased 2 different WH08LS20 drives one retail and one the OEM WH08LS20K version. Neither of them run even close to the rated speeds, the Blu-Ray runs at 1x-2x and the DVD transfer rates are 1x-2x. CD transfer rates is also extremely slow. Tried a different SATA cable, restoring defaults in BIOS, switching to antother SATA port, nothing. Hard drive is working fine. Really frustrating, let me know if you have any ideas as to wheter it is a software issue or I should replace the drive. Using Windows 7 64-Bit Home Premium.[/QUOTE]
It would be very helpful if you can tell us the exact motherboard and CPU you were using. Some motherboards require the installation of their own SATA drivers in order for their SATA ports and SATA controller to work properly. And check the Windows device manager and the Advanced Settings for the ATA channels you have the BD drives connected to. Your system might have defaulted the specific ATA channel to PIO-only mode when you first installed the drives with no way at all whatsoever to enable DMA (the check box is grayed out). If the latter is the case, then try uninstalling the Windows entry for that particular ATA channel and restart your system. Let Windows redetect and install drivers for that ATA channel. And while you’re still in the Windows Device Manager, check for any yellow exclamation marks next to your ATA controllers and/or optical drives.