You can play Fortnite and PlayerUnknown's Battlegrounds (PUBG) on pretty much anything. Both games support a wide variety of hardware, and with their fairly extensive graphics options, it's not hard to get decent performance from most setups. But a pair of players have found out there are hidden benefits to playing these battle royale titles on a system that can push as many frames as possible.
Intrepid players of both games, WackyJacky101 on YouTube and u/0x011A on Reddit have discovered that frame rate directly affects how quickly guns fire. It appears to be a relatively simple relationship: more frames per second, more shots per second. However, things are actually slightly more complicated than that for PUBG, and people are still investigating on social media. The problem appears to result from a flaw in Unreal Engine 4, and because Fortnite and PUBG were both made with that engine, it affects them as well.
How does this affect gameplay?
This flaw probably wasn't the reason you last died to someone in either battle royale. All other things—your skill level or equipped weapon, etc.—would have to be equal for that to be the case. The odds of that happening in a given match are minimal.
But a big part of the battle royale genre's appeal is that games aren't pay-to-win (with the exception of certain emotes offering unintended benefits players can exploit). Nor are they limited to team-based modes where your chances of victory depend on the quality of the matchmaking system. Everyone is supposed to be on a level playing field at the start, with the only real advantages they can get being the equipment they find strewn about the map.
Having a higher fire rate than someone else because your system can push more frames than theirs wdefy that concept. Sure, better hardware can offer certain out-of-game advantages, like a smoother experience. But this is a measurable in-game advantage, not a matter of personal preference.
A tweet from Fortnite's Twitter account responded to streamer Benjamin “DrLupo” Lupo’s tweet about this issue. Lupo has casted several Fortnite tournaments in addition to streaming the game to thousands of subscribers; his tweet was bound to get the company's attention.
"Thanks for bringing this to our attention. We're aware of this issue and are investigating a fix for it," the Fortnite account's response said.
It's not clear if Epic plans to fix the issue in Fortnite or, if it's Unreal Engine 4's fault, the engine itself.