Sony recently released firmware 2.0H for the DRU500AX and DRX500ULX units. And the improvements are: Allows your Dual RW drive to record at 4X on 4X compatible DVD-/+R media. Improves reading and writing performance and reliability. Reduces vibration noise for the discs with unbalance or eccentricity. Improves audio playback on written discs with stand alone systems. Improves reading and writing performance with 8cm DVD-R/RW.

Sony DRU500AX Sony DRX500ULX