Slow/Bad screen recording
 

I wanted to record my screen/make screencasts, but I get so bad results like recording with only 3fps. I want to record the game Minecraft, I play with 150fps. There is only one exception, if I record with recordmydesktop on Gnome3 or LXDE the video is really smooth but on Unity I get again so bad results with this programm. I tried a lot of programms, Kazam, FFmpeg, Eidete, recordmydesktop and Xvidcap. I even tried older drivers and Beta drivers.

I hope that someone can help me.

My system Specs:
- Ubuntu 12.04 64bit/32bit
- AMD Phenom II X4 945 Processor - 4x 3.00Ghz
- Geforce GTX 550Ti by Club3D
- Biostar NF520D3, Pcie 1
- 8GB DDR3 Ram
- Driver: 295.49, 295.59, 302.07 Beta, 304.22 Beta

Peter