Question / Help Anyone successfully using SLI without Vsync with OBS-MP?

Hello,

Have been working on OBS and now OBS-MP for a couple of months (off and on...) trying to get a config set up that will allow me to run a particular game (H1Z1) in SLI with a pair of GTX 980 Ti's -- without having to use Vsync.

Basic system specs:
Asus X99-E WS board
i7 5960-X - stable at 4.375GHz
32GB RAM
(2) Nvidia GTX980 Ti's in SLI
Windows 7 x64, SP1
64-bit versions of OBS and OBS-MP tested

I'm running the game at 1920x1080, downscaling to 1280x720 with lanczos, trying to output a stream (to my transcoder PC) at 60fps.

The game plays fine at 150+ fps, but OBS-MP just can't keep up - it drops a LOT of frames. I have tried with Multi-Adapter Compatibility both off and on, anti-cheat compatibility hooking off and on, Game Capture vs. window capture, etc. etc. I tried enabling the Limit Framerate checkbox while I experimented with Game Capture, to no avail.

(note: Being a Windows 7 user, I remembered from the older OBS software that Game Capture may not be a good choice for SLI but it works about the same with OBS-MP 0.12.2 and has more options in the config -- plus it doesn't leave the preview of the source on the screen when you exit the game like Window Capture does).

I abandoned NVEnc (at least for now) just to be able to try OBS-MP and see if it was any better. I have even (briefly) tried Dxtory with both OBS and OBS-MP. I've tried x264 ultrafast presets at 135 megabits and 0 buffer size -- and veryfast, faster, and fast at 75 megabits and lower down to 25 megabits.

It all seems to come down to the same bottom line: If you show OBS or OBS-MP more than 60 fps, the smoothness of the frames of the output and preview starts falling apart.

Interesting thing I noticed with some testing yesterday: MSI Afterburner (Rivatuner Statistics Server) shows a considerably higher in-game FPS if you turn Multi-Adapter Compatibility *OFF* (if you are using Game Capture instead of Window Capture).

If I settle for using VSync, it does OK for the most part. OBS-MP (0.12.2 as of a few days ago, tried 0.12.0 and 0.12.1 previously) and the legacy OBS can "keep up" and the video it outputs is smooth. I just hate putting the clamp on the video cards to please OBS/OBS-MP when the game plays so well with them allowed to run "wide open" as they were made to do.

It is also a bit humiliating that I can set the game and NVidia control panel to force using 1 video card only (a much more limited amount of testing done with this) and it seems to do a lot better. But why would I want to do that when I paid extra for 2 cards? :)

I'm not just complaining here, and I'm sorry if it comes across that way. I am "pretty technical" just not a developer, and willing to do or test whatever might be needed to help with any of this. I can also provide logs etc. and system details if there is time/ability to investigate this further.

I do realize that at the end of the day, if I want a 60fps video stream then I really don't need more than 60fps. It's just disappointing to have to impose a limit on the video cards when they are capable of so much more.

But if anyone is successfully using a pair of NVidia video cards in SLI with OBS or OBS-MP and not having to use VSync to get stable ouput, I'd love to see how you're doing it. :)

Thanks,
Tackmeister
 
I understand wanting to push your GPUs' limits. But I would think that'd be more useful in upping the graphic fildelity, not cranking out more frames nobody is going to notice. Perhaps you need a game that'll really put it to the test? Like SW Batllefront with that ultra realism mod..
 
Hi DoAGoldeneye. Thanks for the reply.

There is something a little odd/off about H1Z1 and its use of the video hardware. I am reminded that my wife is running Elder Scrolls Online in SLI with a pair of 980 GTX Ti's that averages around 100fps and has no problems with OBS. She also reminded me that she runs with Vsync completely off in-game and in the Nvidia control panel.

The problems I'm seeing may or may not have much to do with OBS or OBS-MP at all.

I do have the graphics settings cranked up pretty high in H1Z1. I actually quit using the in-game UI for the most part 1-2 months ago because there are a lot of settings and "knobs" for stuff the Forgelight engine can do that there just isn't a "clicky-clicky" for in the video settings menu (yet, at least...?) Ha, for example I had to experiment a lot to find exactly how highly above the stock settings options the menu provides that I could increase the pixel supersampling factor to without causing a stuttering issue with scrolling text sources in OBS until you were fully in-game (not just sitting in the menu).

Anywho, thanks for the reply.
 
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