Minecraft screen recording lagging mac?

Recently i've wanted to start recording on my mac. It has 4 GB of ram, and with my settings, i have when i do fn-f3 around 25-30fps, and when i'm not recording around 50-80fps, and even when i'm recording there's a minor lag, but it isn't that bad. But when i open stop recording, and go to watch it, (I use screenflow) the recording is all laggy, even when i was playing it seemed perfectly fine, i have been messing around with my settings, but nothing seems to help it.

Added (1). Forgot to say the game is minecraft

Use OBS try recording your game plays from there.