So I take that back. I tried again and you’re both right – I didn’t monitor the write speed long enough during the burn the first time because it does ramp up to 4x.
It’s just that the speed fluctuates on some MIDs and so does the device buffer (as shown in ImgBurn… a little bit worrisome but the system buffer remains full so dunno if that means anything), which is probably causing the longer burn times on average for “4x” I’m seeing compared to a sustained 4x
Anyways, thanks for the responses. I think I’ll be returning this drive (ext Pioneer, DVR-113NP) because my older int Pioneer DVR-112D detects the speed correctly and gives me consistently better burn quality overall.