DVD Burning problems on 8X

Does anyone know what the problem is? I am using Pioneer A07 with 1.21 firmware. It burns fine on 4X, it’s 8X that troubles me. Even then it’s okay SOMETIMES, but certain media are troubling me. Here goes:

From what I know, 8X burning starts at lower speed then speeds up. DVD burns fine until it gets to that speed-up point at 15%. It makes a pause, drops buffer to 10%… and with most media fails (with POWER CALIBRATION ERROR). It happens only with certain media, while others work normally. Verbatim DVD+R work fine, but Verbatim DVD-R and ARITA DVD-R. They stop at exactly 15% and give our that error message. If only those +R didn’t work, I’d think it’s broken or I don’t have enough power for real. This way I am lost!

Use CD/DVD Speed and check your burst rate.