It goes without saying that the simplest and most effective way of altering your PC's gaming performance is by using the in-game graphics settings. While the auto-optimisers provided by AMD and Nvidia will affect most of these, there are always a few sneaky graphics settings in games that slip under the radar and have a disproportionate impact on performance. Take The Witcher 3, for example, which uses a weird little Nvidia technology called HairWorks. When this is on, it purportedly makes characters' hair look somehow better. In reality, there's hardly a difference in how Geralt's or anybody else's locks look, and yet many people found that the framerate takes a huge 10-15 fps with the feature enabled. Switch HairWork off, and the game suddenly runs brilliantly. There's a similar issue in the graphically-demanding Metro Redux games, where the in-game anti-aliasing has a huge impact on performance that just isn't worth the hassle. If you're playing a game that's not running perfectly, experiment with the in-game graphics settings, keeping a particular eye on any AMD or Nvidia-branded 'special' features that could be affecting performance.