Boner.

"there is actually no VSYNC ON input lag penalty with G-SYNC at this particular frame rate"
wat?
can someone explain this?

VSYNC ON:
- Quake Live renders frame
- Quake Live **WAITS** for vsync. Input lag occurs.
- Monitor displays frame

VSYNC OFF
- Quake Live renders frame
- Monitor immediately displays frame, mid-scan (splice!), creating tear

GSYNC
- Quake Live renders frame
- Monitor immediately displays frame, with new refresh cycle beginning *immediately* at the top edge, no tear.

____

The non-waiting frame rates of GSYNC is 30fps-144fps. Below 30fps, there's the re-refresh (like a DRAM self-refresh cycle) to prevent the screen from going stale. Above 144fps, you end up waiting for the previous refresh to finish, before displaying the new refresh.

In the range (30-144), there's only about ~1ms difference between GSYNC and VSYNC OFF during this frame rate range. If you never cap-out at 144fps, you don't have any waiting occuring. If you try to send more than 144fps in GSYNC mode, input lag differences does diverge because the monitor refreshes faster. But during 30fps through 144fps, there's almost no measurable latency difference between GSYNC and VSYNC OFF (~1ms, for the "is-the-monitor-ready" poll).

GSYNC actually doesn't have a regular VSYNC per se, since it's asynchronous rather than SYNChronous, so it's really actually a special kind of VSYNC OFF (that visually looks like VSYNC ON!) -- because the monitor will start refreshing *immediately* at the top edge (no tearline) rather than *immediately* in mid-scan (tearline occurs). So during 30fps-144fps range, it combines the pros of VSYNC OFF and VSYNC ON, without the cons of either. The "300fps+" players may still prefer VSYNC OFF if they love the extra few milliseconds -- the good news is GSYNC monitors support all three modes (VSYNC ON -and- VSYNC OFF -and- GSYNC).

I knew that 1st part, but that sentence still looks confusing. Looked like you can have vsync enabled with g-sync and there will be no input lag from it(vsync) at those 125fps.
So while using G-SYNC at those 125fps there is no such input lag, like it would be with vsync on.

"If you try to send more than 144fps in GSYNC mode, input lag differences does diverge because the monitor refreshes faster."
Why and how input lag gets higher with g-sync if game sends more than 144 fps?

Will G-SYNC help mask microstutter from "overzealous optimizations on the GPU driver side"?

Aha, you're right.

Perhaps it should be, "Although it visually looks like full frame-rate VSYNC ON, there isn't the input lag penalty of VSYNC ON, and there isn't any of the sudden framerate slowdowns of VSYNC ON". GSYNC is very hard to visually describe, without animations to help, and even animations are still difficult and imperfect.

-- GSYNC is like VSYNC OFF in framerate behaviour & input lag
-- GSYNC is like VSYNC ON in lack of tearing (but no sudden slowdowns)

Above 144fps, the input lag diverges between GSYNC and VSYNC OFF only because GSYNC has a 144fps framerate cap. Once you hit 144fps, it has to finally start waiting for the monitor to finish the previous refresh (much like waiting for VSYNC), so now it behaves like 144fps=144Hz VSYNC ON. Even so, this is more harmless than VSYNC ON because when framerate slows down during GSYNC below 144fps (e.g. 143fps), it will never suddenly halve to 72fps -- it will gracefully slow down. None of the jarring input lag change of sudden frame rate halvings. It is like driving a car with a continuously variable transmission (CVT), rather than a gear shifting effect. You don't feel/hear/notice gear effects. I can't tell apart 142fps, 143fps or 144fps. You do get less input lag at 300fps VSYNC OFF than 144fps VSYNC OFF, but GSYNC doesn't let you go 300fps. Even so, the theoretical maximum input lag divergence between GSYNC and VSYNC OFF is a theoretical 6.9 milliseconds (1/144sec) plus the GSYNC poll time (~1ms), if you successfully get infinite-framerate VSYNC OFF (which is impossible). In the real world, the average input lag diverence of 288fps VSYNC OFF relative to 144fps GSYNC would mathematically be an average of 1/288th of a second difference (only 1/288sec = 3.4 milliseconds extra lag (+ 1ms poll) for GSYNC 144fps versus VSYNC OFF 288fps). Most gamers, except the uber-elite competitive gamers, would not even care about that.

Even with elite competitive gamers, it doesn't matter with Quake Live....It is limited to 125fps so that's below the GSYNC cap. And when you play Battlefield 4, you ain't getting 300fps, either. Since most of the modern games you play, will not cap-out at 144fps, realistically, you won't be hitting the GSYNC 144fps limit. And 144fps isn't necessarily the final frontier for GSYNC monitors later this decade...

No idea about whether GSYNC completely mask microstutters from driver issues, but it will almost certainly reduce them at least somewhat (the monitor would cease to amplify microstutters).

How about resources needed.

This should be helpfull for some valve games running at shit framerates :D in directx

Not only some Valve games, but any game. Honestly I'm thinking more about Crysis, which is hard to run at highest settings and high framerate.

tottaly forgot about crysis! good poing sir!

i'm already preparig for it since i heard from it the first time. :P

(canceled my order of xl2411t, upgraded PC with GTX760)

It's expensive though :/

i had luck that it was announced right when i wanted to upgrade my pc anyways. :)

so it will cost me 50-100€ more in the end.

now nvidia just need to look into the frame smoothing/input lag of their own drivers.

so g-sync probably feels like running a game's fps at twice the refresh rate (so a frame is always prepared for rendering) without twice the fps