Well I've loads of problems burning at 4x with the Sony drive. I have tried several different types of media without any luck. Tried every different configuration of software and hardware I can think of with no success. Sonys fix was to use an 80 wire IDE cable but this made no difference. Also their Record Now software was useless, I could not get it to burn a DVD at all.
My last resort was trying the PIODATA 4x Ritek disks. Burnt about 75 of these with no 4x burns. Tried sony again but they dont seem to be interested. The media is not on their compatability list, what a load of crap.
But finally last night I cured the problem. I spent £86 of a Pioneer A106 and installed in in the space the sony came out of. Success 4x speed burns with the same Ritek media straight out of the box.
So thanks very much Sony for making me a Pioneer customer, thats the last Sony product I will be buying.
Well I've had my gripe for today, back to 4x burning.