G-Sync above 240 Hz - Why use V-Sync?

Talk about NVIDIA G-SYNC, a variable refresh rate (VRR) technology. G-SYNC eliminates stutters, tearing, and reduces input lag. List of G-SYNC Monitors.
Kroosh123
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Re: G-Sync above 240 Hz - Why use V-Sync?

Post by Kroosh123 » 14 Jan 2020, 11:26

I also have the Acer Nitro XF252Q. I came to BB forums to see if anyone else had the same issue with fluctuating frames, specifically reported by the monitor.

Usually I set my max fps to 230 with G-Sync and V-Sync enabled. Yesterday I tried it at 180 as I mostly play Apex and supposedly the game engine has a problem with frame rates above 200. Turned on the Nvidia frame counter and the OSD frame counter. Nvidia reported a rock solid 180, but the Acer OSD fluctuates wildly between 160 and 220. I am inclined to believe the monitor is reporting the correct frame rate it is updating at, even if it is mismatched with what the graphics card is outputting. Leading me to believe it is not a good idea to use G-Sync on this monitor even though it is listed as compatible.

I would love to hear what other user's experience is with this monitor as I know a lot of people on these forums own this monitor.

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Re: G-Sync above 240 Hz - Why use V-Sync?

Post by Chief Blur Buster » 14 Jan 2020, 12:03

Kroosh123 wrote:
14 Jan 2020, 11:26
Usually I set my max fps to 230 with G-Sync and V-Sync enabled. Yesterday I tried it at 180 as I mostly play Apex and supposedly the game engine has a problem with frame rates above 200. Turned on the Nvidia frame counter and the OSD frame counter. Nvidia reported a rock solid 180, but the Acer OSD fluctuates wildly between 160 and 220.
Frame rate counters are necessarily an average over a time period

They may both be correct simultaneously -- they're averaging over different time periods.

160 to 220 might be the correct average for 100-millisecond average, while 180 might be the correct average for a 500-millisecond time period.

Do you know what the mathematical formula sampling rate both averaging sysystems use? If you said "No", then why do you believe one or the other more? They both may be correct simultaneously.

Sure, there can be bugs in frame rate counters, but again, frame rates are an average.
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       To support Blur Busters:
       • Official List of Best Gaming Monitors
       • List of G-SYNC Monitors
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Re: G-Sync above 240 Hz - Why use V-Sync?

Post by Chief Blur Buster » 14 Jan 2020, 12:06

Kroosh123 wrote:
14 Jan 2020, 11:26
Leading me to believe it is not a good idea to use G-Sync on this monitor even though it is listed as compatible.
Actually, it is often the reverse. Erratic frame rates look smooth on a G-SYNC / FreeSync monitor.

Take a look at www.testufo.com/vrr as one example.

Now if you're using non-VRR, this is what happens:
Image

Then with a VRR monitor, such as G-SYNC
Image

By virtue of VRR, it successfully removes stutters from a fluctuating frame rate because the monitor refreshes at the instant the game's ready to deliver a frame. Erratic instantaneous framerates (90fps, 110fps, 95fps, 105fps) can average out to 100fps over a longer time period. Because (90+110+95+105)/4 = 100

So that's why the two frame rate counters may be correct, they're simply averaging over different timescales.

However, it all boils down to the quality of the VRR too (the game, the drivers, the monitor). VRR done well, it looks great despite fluctuating frame rates.

VRR's ability to eliminate single-frame stutters is very good -- but it's longer freezes (disk loading, engine issues, driver issues, etc) that can still create stutters that VRR cannot eliminate. If you are seeing hugely visible stutters, something is a weak link, creating stutters that VRR cannot fix. This would be a completely separate problem than the framerate counter averaging algorithm.
Head of Blur Busters - BlurBusters.com | TestUFO.com | Follow @BlurBusters on Twitter

       To support Blur Busters:
       • Official List of Best Gaming Monitors
       • List of G-SYNC Monitors
       • List of FreeSync Monitors
       • List of Ultrawide Monitors

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