本帖最后由 堕落的翼 于 2023-5-5 19:23 编辑
AMD FreeSync™ Technology¹ FAQ
AMD FreeSync™ Premium is a new tier of FreeSync introduced at CES 2020 that caters to serious gamers.
All FreeSync technologies enable smooth stutter free gameplay. The AMD FreeSync™ Premium tier adds to the baseline FreeSync technology tier with additional benefits such as mandatory low framerate compensation (LFC) and at least 120hz refresh rate at FHD resolution. LFC helps ensure that when the framerate of a game is running below the minimum supported refresh rate of a display, the frames are displayed multiple times so that you can remain in the supported refresh rate of the display and maintain smooth gameplay.
How exactly does LFC (Low Framerate Compensation) on a Freesync monitor work?
LFC keeps even frame pacing just like Freesync, by keeping the monitor in the Freesync range by doubling the refresh over the games fps. So, if the fps drops to 29, the LFC will adjust to 58Hz refresh on the monitor and display every game frame over the entire course of two monitor refreshes. If the fps moves to 34, LFC adjusts the refresh to 68Hz, again holding every game frame up for two monitor refreshes. So on and so forth.
This adjustment happens constantly as fps change. The reason it works is that it always keeps the screen refresh as an even multiple of game fps. The end result is perfectly matched game frames to monitor refreshes, eliminating judder from mismatched fps to monitor refresh just like Freesync does.
On a monitor that does not support FS/LFC, lets say a 60Hz refresh monitor-- 30fps in game will look judder free because its essentially doing what LFC does, displaying each game frame for the duration of 2 monitor refreshes-- but, if the fps goes up just one frame to 31 (or goes down, but we'll just use 31 for example), then its no longer mathematically possible to hold every fps for the duration of two monitor refreshes. It can be handled one of two ways:
1.) 29 of the frames are displayed evenly for every 2 refreshes or 58Hz, and the remaining 2 frames (remember we have 31 total) will be displayed 1:1 per monitor refresh for refresh 59 and 60.
2.) 30 of the frames are displayed evenly over that 60Hz refresh and 1 frame is "skipped/not displayed".
In scenario 1, 29 frames have a duration of ~32ms each and 2 frames have a duration of 16ms. In scenario 2, 1 frame of animation is not displayed at all. In both cases, you will experience a "hitch" or "stutter" every second. |
310112100042806
发表于 2023-5-5 12:34
