BattlEye Anti-Cheat has an extremely limited influence on the framerate, so it is not a cause for any concern.
Here is a quick run-through of the anti-cheat’s impact on framerate. Inside the game there are two places where we run BattlEye, which could block the execution of the game.
There is a BattlEye update every frame and a BattlEye packet update about every second.
The packet update is by far the most expensive, so let’s just assume the worst case and pretend we have to process a packet every frame.
We should also assume that the game runs poorly, so let’s assume the game runs at 20 fps.
Based on our in-game timers we measure the BattlEye packet update to take about 0.1 milliseconds on average, but let’s assume the worst case and pretend it takes 0.5 milliseconds (5 times the average time).
We can now calculate how big a percentage the worst case BattlEye update is out of the whole frame.
At 20 frames per second a single game frame lasts 1/20fps = 0.05s = 50 milliseconds.
So the BattlEye packet update out of the whole frame is 0.5 milliseconds / 50 milliseconds = 0.01 = 1 percent.
So the worst case average is that BattlEye takes 1 percent of the frame time, which is not a cause for concern.