Re: How can I minimize input lag on fallout 4 ?
Posted: 13 May 2018, 02:08
Thank you for the post.RealNC wrote:Nope. This only happens when the game takes longer than 16.7ms (with 60Hz vsync) to actually render the frame. The FPS halving only occurs when render times are too long, not when frame presention times are too long. An FPS limiter controls frame presentation times.KKNDT wrote:But I still have a question. Wouldn't it cut the frame rate to half of the refresh rate due to the frame time being longer than a refresh cycle(Assuming the system is very powerful) ?
In other words, a game that is susceptible to this would experience FPS halving if it would, say, run at 50FPS uncapped. But if it would run with 60FPS or higher when uncapped but you use a frame limiter to artificially cap it to 50FPS, then there will not be any FPS halving; the game will simply run at 50FPS instead of 30, even with vsync ON.
This is because when using a frame limiter, the back buffer (the buffer that holds the frame to be displayed next) actually contains a frame that is ready. It's just being held back by the frame limiter. When the game is unable to reach the frame rate cap however, that means the back buffer is NOT ready yet - the game is taking too long to render the next frame and put it into that buffer. So since there's no frame in the back buffer, there's nothing to send to the monitor when the vsync signal occurs, and instead the front buffer is sent again to the monitor. That means the frames are displayed twice, and thus FPS is halved.
So can I understand in this way?
If the game runs at 100 FPS uncapped,it takes ~10ms to render a frame. Now you give it a 50 FPS cap, it will still take 10ms to render a frame, but will hold back ~10ms before start to work on the next frame?