Hi all, need a little help to reproduce 60hz / 120hz issue

[BattleAxeVR]

Hi forum, it's been a while since I posted here, but I'm working on a project involving high framerate display duplication and ran into a Windows issue that I was hoping to get some feedback on.

It's very simple, windowed 3D apps shown on multiple monitors will be reduced to the lowest common denominator refresh rate among the monitors.

Say you have one 1080p 60hz TV or monitor, as well as a higher end 120 / 144hz monitor, and you open any two of these links (or indeed any 3D windowed app, not necessarily running in a browser):

http://www.fishgl.com/

or

https://www.shadertoy.com/view/XlscDH

or even Blurbuster's very own:

https://www.testufo.com/frameskipping

Can you tell me if you notice the FPS drop on the higher refresh rate monitor to match the lower one when you drag one window to that monitor?

And it goes back up when you drag it back to the other one?

I'm wondering if this happens with AMD, and not just NVidia (I have a GTX 970). I tried disabling transparency and all fancy stuff on Windows 10, same thing.

This happens 100% of the time for me, no matter what game, or app, or browser I use, and I think is an unfortunate way that Windows 10 compositor works with 3D content.

I wonder if there's a registry hack or NV driver setting I can use (multiple monitor performance mode seems to have disappeared in the driver recently?)

Switching to fullscreen on the high-hz monitor and leaving the offscreen one running seems to de-couple the refresh rates again, which is a relief and a valid workaround, but still not ideal.

I'm trying to find a solution to this issue, and was wondering if anyone here has any ideas.

Thanks in advance!

[Chief Blur Buster]

In my years of TestUFO, it has always happened with Google Chrome, and a very recurring "TestUFO stuck at 60Hz" problem -- google "TestUFO Stuck at 60Hz" for examples. This was a problem even in Windows 7 days too, something I discovered as early as 2012-ish...

That's why I frequently advise people to use single-monitor when gaming and or testing TestUFO, to prevent refresh-rate interference between a high-Hz primary and a low-Hz secondary.

The common situation is people keep their 60Hz monitor when buying a high-Hz monitor, and use that 60Hz monitor as a secondary -- not knowing that it can sometimes lag games or sometimes reduce framerates of Windows apps.

The best action for eSports is temporarily disable secondary monitors when playing lag critical games, then reenable. Ornuse a utility such as DisplayFusion to switch between multimonitor profiles.

[BattleAxeVR]

I read that NVidia removed their multi-monitor performance mode option in their driver a few years ago. I'm going to try and ask a contact I have at NVidia if there's a registry setting to enable it.

It would be good to get confirmation that this happens for AMD users too, but I suspect it will, since I tried plugging in my second display into my motherboard's Intel GPU and it still happened. Although, it's not clear whether that necessarily used the Intel GPU since it's treated as secondary in the enumerated list of GPUs. I have a DX graphics sample where I can pick which GPU to render with, to see if that changes anything. If not, then it's clearly Window's fault.

The only way around that, assuming MS won't fix it (who knows, they might, but this is fairly "fringe") would be to use GDI instead of DX swap chains, or something like how VR compositors to bypass desktop mode. E.g. the Rift and Vive are hidden from the display settings even though they are technically just HDMI monitors which normally get detected under the hood in the same way. If the graphics drivers detect a certain EDID they go into a special "stealth" mode which can be disabled by a registry hack, at least for StarVR headsets.

From what I remember, too, the "stealth" display mode also has better performance (less latency).