jshc1: I've no problem with loosing 200Mhz (the cooling plate still gets quite hot sometimes), but I would have if the system uses the wrong cores for the hard work.
Thanks to your hint I detected htop was set up wrong. I don't know how this happened, but hinstead of showing CpuFreq1 to 8 it was showing the variable CpuFreq (without any number) 8 times. CpuFreq only showed the "little" CPU freq.
So, thanks to this hint, I consider this issue solved. :-)
Letterus got a reaction from devman in /proc/cpuinfo show only .LITLLE cores on Odroid-HC1 - hints appreciated