kurtextrem wrote:I don't think csgo pros are playing with gsync when they're able to get 800? fps or so.
Correct, many eSports pros like VSYNC OFF because massive framerates can bypass scanout lag. This image is useful to understand why competitive and eSports players love VSYNC OFF -- at ultra high frame rates, scanout lag becomes noticeably bypassed!
This illustrative example, at 432 frames per second at 144 Hz, VSYNC OFF -- creates three frame-slices per refresh cycle -- multiple tear lines per refresh cycle.
We have invented the "Filmreel" metaphor based on high speed video analysis. I have analyzed lots of high speed videos (4 frames rapidly alternating in a cycle), and have observed how display monitor scanout interacts with lag.
One of our most popular high speed videos, is our
old high speed video of LightBoost. In non-LightBoost mode, the gaming monitor LCD display clearly scans from top to bottom. Bottom edge always has more input lag! But "VSYNC OFF" actually "cheats" this by interrupting the current scanout with a new frame. We have newer high speed videos (which we will release soon) that clearly illustrate why we invented a filmreel metaphor of explaining scanout latency.
CRT/LCD/OLED: Capable of synchronous scanout directly from the cable, top-to-bottom wipe.
Plasma/DLP: Require scan-conversion (to a non-sequential scan method, such as globally-flashed temoporally dithered subfields).
On displays that synchronously scan from the cable (cable scanout = same speed as panel scanout)....
....When you have 1000fps VSYNC OFF (1 frame = 1 ms), each frameslice adds only 1ms lag relative to the GPU output. As the display scans out seqeuentially, it can continue to display the next frame (with tearing in between). Obviously, many subtle lag factors apply (mouse, cable differences, LCD GtG, etc), but scanout lag is definitely part of the input lag equation, including bottom edge of previous refresh cycle.
Lag can dramatically go down when even the bottom of the screen has only 1ms input lag -- which is faster than the sequential 1/144sec scanout of a 144Hz display. VSYNC OFF can "beat" scanout latency by interrupting the current finite-speed scanout with a new (fresher) frame to hit your eyeballs sooner.
CS:GO and Quake, both still popular today, both achieve 1000fps in VSYNC OFF on current graphics cards.
Once you "spray massive framerates" -- an overkill VSYNC OFF framerate (e.g. 1000fps) -- onto the video cable and onto the display, it noticeably has less lag than GSYNC or FreeSync since it crams a lot of tiny low-lag tearslices to the same refresh cycle that "beats" the scanout latency consistently, every refresh cycle.
1/144sec refresh cycle is
6.9ms scanout lag for bottom edge, mandatory, because of finite speed of display scanout.
1000fps VSYNC OFF can reduce this to
1ms lag by continually interrupting the scanout with fresh frameslices (1000fps = 1ms per frame slice).
That few extra milliseconds savings (+1ms "frame-to-scanout" lag instead of +6.9ms "frame-to-scanout" lag), that extra ~5ms "best-case" competitive advantage (relative to 142fps frame-capped 144Hz GSYNC or FreeSync) can cause you to win the frag in simultaneous-draw situations (equal human reaction time scenarios, shoot-eachother-at-same-time). Screen centre is half that, but some competitive players are primed to react by peripheral vision to bottom edge first (e.g. close-quarter combat or explosion flashes).
This may not matter in novice competitive gaming, but can matter in the elite paid eSports leagues when the bottom edge has almost a full refresh cycle less lag during "overkill framerate VSYNC OFF" situations. This is why you hear many eSports players say they don't use GSYNC.
The higher the max refresh rate (e.g. 240Hz), the faster the scanout is. VSYNC OFF will probably become slightly less important once framerates consistently stay below monitor's maximum refresh rate.
So we need 1000Hz monitors to allow GSYNC or FreeSync to fluctuate nicely between 200fps and 999fps in games like CS:GO and Quake. As we approach this, VSYNC OFF may be able to gradually become unnecessary even in eSports. Then -- simultaneously -- we'd have virtually no lag AND no tearing AND no microstutter. And blur-free "1ms persistence" at high frame rates without adding lag of strobing.
eSports holy grail?
It's going to take a long time before that happens, but anytime framerates go beyond refresh rate, there's still the potential to have quite noticeably less input lag during VSYNC OFF (scanouts that can be interrupted, with a new fresher frame, on the fly, in real time).