Hello and welcome to the OBS Community,
First, it's not really possible to do a recording of one minute who weight 150 mbs except if you record in 480p 2,4Mb/s and the quality should be quite bad so... For the file weight you're not quite in it, but if you want to sacrifice the file size and record in good video quality you should try these settings :
- Resolution : 1920x1080
- Bitrate : 7500 Kb/s
- Audio bitrate : 192 Kb/s
- Video format : libx264
- Audio format : aac
Next, the only difference between AMD encoder and other encoder is the performance impact, the AMD encoder use both the CPU and the GPU so this encoder is much better cause it decrease the performance impact on your computer and is definitely the way to go!