MakeMKV inconsistent read rate from Blu-Ray reader

[multimiler]

I'm running a MacBook Pro 15", with Yosemite 10.10.1, and a ASUS BW-12D1S-U Blu-Ray reader.

Tonight I had a half-dozen new DVDs and Blu-Rays to rip. I started with "The 10 Commandments", but noticed that it was only ripping at 2.0X and was going to take over an hour. So, I decided to rip some of the DVD's first (8-10 minutes each), and rip "The Ten Commandments" last.

As stated, the initial rip maxed out at 2.0X. But after ripping all the DVDs, when I returned to rip the "The Ten Commandments" again it immediately started ripping at 7.0X. Why the inconsistent rip speeds? Why can't MakeMKV use the higher rip speed from the beginning?

This is very frustrating

[Woodstock]

There is more data per track on DVDs and BDs as you move out from the center. Disk rotation speed is a limiting factor... you do not want a disk flying apart inside the drive (trust me on this!), so read rates are more limited at the beginning.

That said, I have had some BDs take an hour to rip. There can be issues with the way the disk was created that can affect how fast its data can be read, and it is possible that the BD+ mangling can affect the speed of read.