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Alienware AW2518H G Sync

Posted: 10 Sep 2019, 22:29
by NikNargon

I just purchased an Alienware AW2518H and was hoping someone could help me with something as I'm a little confused.

I’ve got G Sync turned on in nvidia control panel and it seems to be registered in the monitor’s OSD (mode says G Sync) but when I’m in a game and I check the OSD it always says the current refresh rate is 240HZ even if the FPS is below that.

If I turn on the G Sync display banner in nvidia control panel it displays the banner while in game saying G Sync is on, but I would expect the OSD to show the current HZ as matching the FPS in game rather than 240HZ all the time. I had previously used the Freesync version of this monitor with G Sync compatibility and that's the way the OSD behaved (ie. would show the current HZ as matching the FPS at the time the option was selected).

I've tested with the Pendulum demo and I think that G Sync is working:

- I dropped the HZ to 60 on the monitor so the stutter/shakiness would be more noticeable with the non G Sync tests (at 240HZ it's not so pronounced)
- I simulate 40-60fps and there is noticeable stutter and shakiness on the pendulum with both V Sync and V sync off modes
- I select the G Sync option and the motion is smooth as you would expect to see with G Sync working
- When I check the OSD with the G Sync option on the HZ is reported as 60 regardless of framerate

Is there just a difference with how the OSD functions between the 2 models (ie. Freesync/Gsync) or is there something wrong with my G Sync monitor/chip. The monitor has been running great besides this quirk I've noticed, but not sure if that's just a natural result of 240HZ or if the G Sync is actually functioning as expected.

If anybody who owns this model could check theirs I'd really appreciate it.


Re: Alienware AW2518H G Sync

Posted: 11 Sep 2019, 13:52
by RealNC
That's normal. The OSD tells you the current mode's refresh rate, regardless of current FPS. When you use 240Hz g-sync, the scanout speed is always that of 240Hz (4.17ms), but the refresh rate matches the FPS. This is the better behavior IMO, because that way you can verify if you're really using 240Hz g-sync or not because some games sometimes force a lower refresh rate (Skyrim for example used to do that.)

Some monitors also have an "FPS indicator". If you enable that, then the current refresh rate would be shown. Not all monitors have that though.

Re: Alienware AW2518H G Sync

Posted: 11 Sep 2019, 17:51
by NikNargon
Thanks RealNC, appreciate the response, and what you're saying makes sense. This monitor does have an FPS indicator and it does match the FPS in game.

I was doing some more testing with the pendulum demo since posting and was hoping you could help me understand how LFC works with G Sync - If I set the FPS really low in the demo, for example 20 FPS, the monitor's FPS counter shows 20 (and the stutter is really bad). With how I understood LFC to work shouldn't the monitor's FPS counter show 40 when G Sync is on (ie. shouldn't LFC double the frames to fall within the 30-240HZ G Sync range or have I got that totally wrong)?

This isn't ever going to be a problem in real world usage as my FPS never falls that low, but was just one of the tests I was using to see if the G Sync chip was operating correctly.

Thanks again for your help.

Re: Alienware AW2518H G Sync

Posted: 12 Sep 2019, 11:41
by RealNC
It just seems the FPS indicator displays the incoming signal's rate. LFC on native g-sync displays is done by the monitor (the g-sync module,) not by the GPU, so the FPS indicator can actually display what the monitor is getting.

Re: Alienware AW2518H G Sync

Posted: 13 Sep 2019, 07:42
by NikNargon
Cheers RealNC, the info's been very helpful.

Re: Alienware AW2518H G Sync

Posted: 17 Sep 2019, 11:25
by TTT
This doesn't sound right..

If my Gsync is on, any fps display shows what fps I am getting in game, not the max hz of the screen.

So say I have my monitor set to 240hz gsync, force max refresh and I peg Apex Legends to 80FPS.

My RSS frametime and FPS will read 80, my geforce overlay will read 80 and my OSD refresh activited on the monitor will read 80.

OSD only constantly reads 240 when Gsync isn't on.

Re: Alienware AW2518H G Sync

Posted: 17 Sep 2019, 22:33
by NikNargon

Just want to confirm, with the OSD refresh activated are you talking about the monitor OSD real time display (accessed under the OSD menu 'Game Enhancement > 'FPS Counter') or the static display that is under 'Other' > 'Display info' (which lists 'Current Resolution' and 'Max Resolution')?


Re: Alienware AW2518H G Sync

Posted: 18 Sep 2019, 06:52
by TTT

Yes its the same as your OSD FPS counter, I have an Acer predator so settings screens are a little different though.

It comes up in the rop right in big yellow numbers.

Re: Alienware AW2518H G Sync

Posted: 21 Sep 2019, 00:24
by NikNargon1
For some reason my original account can't reply so had to create again.

Ah ok, thanks. Yes my monitor OSD counter functions the same way, ie. will show the current FPS.

In the Alienware there's a section in the display info that shows the current resolution (pixels and HZ). I have both the G Sync and Freesync models and what had confused me was the Freesync one shows the HZ as matching the FPS at the time you select the menu option, while the G Sync one displays the current scanout speed (ie. 240HZ) even though the FPS counter correctly reflects the in-game FPS. I think it's just a difference with how each model handles that menu option.

I spoke with Dell originally as well and they provided the same info that RealNC did. Also has been performing great in games so think it's all good.

Appreciate you taking the time to provide input though, thanks for that.