If you are ripping a double layer than it will reach 8X at the end. It always start around 2.5X and slowly increase to reach 8X at the very end.
If you want a faster rip speed you need to dowload this firmware and this patcher . You unzip both, open the firmware with the tool, click on "general patches", enable the speed you want, save the firmware to a different name, and flash your drive with the new FW.
Don't try to change all the speeds. The only ones you need to change are DL (+/-), dvdrom DL, and +/-R.
The best speed are: 12X for dvdrom DL, and +/-R.
8X for +/-R DL
Please if you don't know what you are doing read the "read me" file that is with the Omnipatcher.