I have for few months a GH20NS10. I like it. But ....
There are some strange things with it.
It could read normally. I remember I tested DVD DL reading and was at 12x as it should be. For the moment it can't read at 16x speed a DVD R and DVD DL is read on the first layer at max 12x and from the second layer it start to get lower the speed starting at 8x not from 12 as it should be normally.
I changed the SATA port of the cable. The same results...
I can figure now that I didn't changed tha SATA cable, but however it can write at 16x speed, even 20x.
I made test using Verbatim MCC 004 written at 20x.
I use Win XP x64 SP2 and my other SATA unit (PIONEER DVR-215) is working fine. My motherboard is one ASUS M2NPV-VM with nForce 430 chipset.
What do you think should be the reason for my GH20NS10 's read problems?