If you have an Nvidia graphics card, you’ve probably heard of ShadowPlay. It’s a feature that you can enable so that when you press a key bind, it saves the last X amount of minutes to a folder on your PC. It’s constantly recording using a hardware encoder for a limited hit on your GPU, and it’s something that you can’t really get on any other hardware. AMD’s equivalent is ReLive, but it pales in comparison to ShadowPlay and its performance. However, with OBS, you can make your own ShadowPlay that works on any machine… and yes, it even works on Mac and Linux.
OBS has a feature that you can enable called “Replay Buffer.” It does the same thing as ShadowPlay and ReLive, except instead of actively writing temporary recordings to the disk, it stores them in your system memory.
This is actually quite a good idea, and I really like that it is cross-platform. If you use Steam Games, they also came out with an auto-record feature that can easily save that last 2 hours (or longer) of play. I’ve been using that on Linux the last month or two.
See https://www.xda-developers.com/how-turned-obs-shadowplay-replacement