on my scans:
read => yellow
write => white
Some time ago I bought new BenQ DW1620 OEM with f/w G7H9 and flashed
it to B7P9 with WinDWFlash.exe and .cvt file.
Drive was made in September 2004.
I returned it to service due to problem with recognizing -R media on
this drive but recorded on others (NEC ND-3500, Lite-On SOHW 1653S).
As I remember I didn't get reading spikes (sure 99%).
They replaced the drive on the same made in September 2004.
Then I flashed my BenQ using other method described on this forum.
Downloded these ones:
and change in hex editor some bytes to allow it to flash into my drive
with current firmware (B5A9 -> G7H9), picture below.
So it was like this:
G7H9 -> B5G9 -> 1600-1620_B7K9 -> B7P9
After that BenQ still couldn't recognize -R disks from other recorders
and more I got reading spikes like you and during that drive slowed
down every spike even at 8x speed test but not always. Sometimes after
reboot I got good scan with only one spike.
Second time I send this drive to service and recieved OEM but with
B7T9 f/w and made in January 2005.
Now BenQ reads all -R disk which I couldn't get to work before and
scans looks good, some I did at different speeds.
Maybe in my case doing DW1620(OEM) -> DW1600(B5G9) -> DW1620(B7P9)
caused this problem with spikes ???