(Since the problem involves two units and at least one disc brand, I placed it here; it could also go to the Benq or Pioneer forums depending on which unit is considered responsible)
The situation is like this: when I scan DVD discs on a Benq 1655 (BCDB original fw) unit I sometimes get high PIF spikes (see pictures). This happens on maybe 50 % of the burns, the others are excelent (these would be too, were it not for the spikes). The discs are written on a Pioneer 111D unit (1.23 original fw), at 4x - 8x speed. The discs in question are Verbatim 16x +R made by CMC. With other brands I haven’t noticed these results, however this has been my brand of choice for some time.
I scan at 8x with Nero CDSpeed 4.60. I also tried scanning at 8X P-CAV and the spikes disappear. On these discs and this unit, the spikes are usually consistent: they show up identically in all consecutive scans of the same disc (there have been rare situations, one or two, when the spike dind’t turn up in a second scan). They have turned up in almost any place on the disk; there is always just one large spike (or none at all). However the read test is always fine (absolutely no drop in read speed near the spike location, or anywhere for that matter - see pictures).
The discs are written by the 111D in Windows XP on an AMD Athlon XP 1800+ with 512 MB RAM and a VIA KT400 Gigabyte MB, the power supply is of good quality and has twice the power needed, the writer (111D) is connected as the secondary master (along with a hdd); I burn with Nero 6.6 and there are no other major applications running during the process, no FW or AV. As far as I can tell, there are no differences in the burning process between the discs with spikes and those without (same hardware, software, no other applications running, no changes in the environment). The scanner (1655) is set as master alone on it’s IDE channel (the two drives are evidently part of different systems).
I am tempted to belive the discs are fine and the scanner (1655) gives false indications. It has shown similar spikes with discs written on an LG 4163 (and fine read tests), also on maybe 50% of the burns (the famous incompatibility); on the discs written by the Benq itself, there were horrible spikes on TYG02 (which I thing were real) and inconclusive (yet generally mediocre) results with Verbatim 16x. However I don’t have any other unit to scan on at the moment, so perhaps you can share your opinions.
And the pictures:
I am first interested in the true quality of the 111D burns; then in the scanning ability of the 1655.
Thanks four your qualified and ontopic opinions.