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G-Sync - smooth, but still blurry?!

Posted: 14 Jun 2014, 11:33
by MonarchX
I was checking out more of G-Sync and realized that while it prevents stutters and such, the image can go from clear to blurry, depending on the framerate. Does that not get in the way of the whole experience if you have medium/low-end hardware? It doesn't work with G-Sync, so even at 120fps, the image is blurred during action. Having action go from somewhat blurry to very blurry due to framerate fluctuations sounds quite annoying! Not hating though - just thinking out-loud!

Re: G-Sync - smooth, but still blurry?!

Posted: 14 Jun 2014, 13:06
by Chief Blur Buster
MonarchX wrote:Having action go from somewhat blurry to very blurry due to framerate fluctuations sounds quite annoying! Not hating though - just thinking out-loud!
Apparently it is not annoying for your unavoidably-fluctuating-framerate games - I found it is a surprisingly very subtle effect. Far less noticeable than tearing and stutters.

GSYNC 120fps looks like regular 120fps@120Hz with the same amount of blur.
GSYNC 60fps looks like regular 60fps@60Hz with the same amount of blur.
You can see the different blur effects of different framerates at http://www.testufo.com

Now with GSYNC, 87fps looks like perfect 87fps@87Hz. And 53fps looks like perfect 53fps@53Hz. On GSYNC, the framerate IS the Hz. The Hz changes every single refesh, even hundreds of times per second. It looks like permanent perfectly-synchronized VSYNC ON motion. When the framerate fluctuations are only about 20fps, I do not even notice the blur changes. The change from 100fps to 80fps only increases the size of blur by (100/80)ths, which is less than 30%. And often, framerates fluctuate up and down slowly, as you turn towards complex scenery. In fact, random framerates 40-70fps looks nearly identical to perfect 55fps@55Hz motion since the rapid modulations in the blur trail is not noticeable because the blur modulations are essentially lost in the blur itself. What is almost miraculous is that slightly (+/- 20fps) varying framerates look like one solid locked framerate, if you are sensitive to stutters. It has the permanent capped-out VSYNC ON look in games that play well with GSYNC.

What happens is that 120fps framerates slowing down to 60fps will have a continuously ramping effect of motion blur similar to www.testufo.com/stutter#demo=gsync (Software interpolated emulation; the real thing is better). Turn off strobing (Lightboost/ULMB/Turbo240 OFF) when looking at that link, in a supported 120Hz browser staying in solid green VALID 120Hz mode, to make the GSYNC emulation reasonably accurate. You do not want external browser stutters to interfere with this specific motion test, check rouser requirements at www.testufo.com/browser.html

Instead of erratic stutters or tearing (non-GSYNC) as you gradually slow down framerate, you instead get a comfortable continuous ramping effect (GSYNC).

If you use strobing on the EIZO FG2421, then high steady framerates look better (e.g. 120fps@120Hz). But try Crysis 3 at Ultra settings, if you are not using multiple Titans, your framerates are all over the map, with frame rates going far lower than strobe-supported refresh rates. In this situation, GSYNC looks far better for low variable framerate situations.

Not everyone sees the benefits of GSYNC - for example, if you can play consistently above 100fps in your games! you may find you prefer strobing or ULMB.

Re: G-Sync - smooth, but still blurry?!

Posted: 14 Jun 2014, 13:19
by MonarchX
Yeah, that is what I though. Does G-Sync add/reduce input lag? Do you have to have V-Sync enabled with it or does it automatically for you to enable it?

Re: G-Sync - smooth, but still blurry?!

Posted: 14 Jun 2014, 14:48
by RealNC
MonarchX wrote:Does G-Sync add/reduce input lag?
It reduces input lag considerably when compared to v-sync. It adds a very small amount of input lag compared to no v-sync and no g-sync. I think in the order of 3ms or such. In comparison, 60Hz v-sync adds 17ms, plus buffered frames (depending on the game and settings) which can result in input lag upwards of 30ms. G-sync gets rid of all that since from the perspective of the game, it's just running with v-sync off.
MonarchX wrote:Do you have to have V-Sync enabled with it or does it automatically for you to enable it?
The point of G-Sync is to get rid of V-Sync. In the nvidia control panel, you select either v-sync or g-sync.

In the in-game settings of games, you should disable v-sync. When running in g-sync, the game really just runs without v-sync and outputs frames as fast as it wants. The g-sync module then updates the monitor every time a new frame is sent.