Question / Help NVENC Performance hit

[D2ultima]

I still don't see the benefit in streaming with vsync on. In 99% of the cases I'm staying over 60fps anyway while streaming so why cap it?

Your point about SLI is a good one though. I do plan on adding a second 970 sometime soon so that should work out well.

On a 60Hz screen, the extra frames are pointless, unless playing CoD or CS:GO where you want 125fps constant or 128+ (if on a 128 tick server). That's why vSync. If you had a 120Hz screen it'd be another matter entirely.

SLI WILL NOT WORK WELL WITH OBS. Not unless you want to use OBS multiplatform. Game capture will grab 1/2 the frames. Window capture will cause intermittent lag. Monitor capture will work only with Windows 8 or 8.1 and borderless windowed games.

 

[Timothy003]

What GeForce driver are you using? NVENC's performance profile has changed significantly in the last few months.

 

[Kashiro]

On a 60Hz screen, the extra frames are pointless, unless playing CoD or CS:GO where you want 125fps constant or 128+ (if on a 128 tick server). That's why vSync. If you had a 120Hz screen it'd be another matter entirely.

SLI WILL NOT WORK WELL WITH OBS. Not unless you want to use OBS multiplatform. Game capture will grab 1/2 the frames. Window capture will cause intermittent lag. Monitor capture will work only with Windows 8 or 8.1 and borderless windowed games.

I'll keep that in mind, thanks.

What GeForce driver are you using? NVENC's performance profile has changed significantly in the last few months.

I always update to the latest available driver. Currently running 352.86 that came out today.

 

[Timothy003]

What NVENC preset are you using? Have you tried the High Performance preset? I'd love to see a log file of a session with the game running.

Also, make sure your GPU isn't throttling.

 

[Kashiro]

I'm using High Quality right now, I've already tried changing the preset but that didn't do anything really. I'll post a log file here tomorrow after work.

 

[Kashiro]

Here's a log file. It's about 5 minutes long from streaming The Witcher 3.

 

[Timothy003]

Turn off CBR padding and set a keyframe interval. CBR padding is the only thing that's changed in OBS, so if you're still seeing a big performance hit after disabling it, it's probably the driver. OBS uses CUDA to interface with the driver, and there are known issues with this, starting with driver 347.09. You can try a driver that worked well for you before to see if that's the case.

 

[Kashiro]

That had no effect either sadly. Still seeing the same performance hit. I'll try rolling back my drivers sometime tomorrow to see if that actually fixes it.

Thanks for the advice so far.

 

[Kashiro]

I tried rolling back to a driver before 347.09, but that didn't do anything either. I'm honestly starting to question myself if the performance hit was always there already or not. In any case, it's still weird that the performance hit is so severe compared to Xsplit/Shadowplay.

 

[D2ultima]

I tried rolling back to a driver before 347.09, but that didn't do anything either. I'm honestly starting to question myself if the performance hit was always there already or not. In any case, it's still weird that the performance hit is so severe compared to Xsplit/Shadowplay.

Remember that performance hit is not only from the selected encoder, but also the capture method. Since Xsplit (as far as I know) does not have a "game capture" function yet, you'd have needed to grab the game in another way. There's various factors. Also, Xsplit has a tendency to grab as much power as it feels it needs from a PC and then let games handle the rest... so in most cases, Xsplit's performance hit would be far far worse. But OBS takes only what it needs, and your games/programs run free. So if the bottleneck is showing up as a result of say... your GPU being maxed out and trying to use non-driver-level NVENC, then the performance hit could potentially be bigger than what Xsplit would bring, because when using Xsplit it's unlikely your GPUs would absolutely max out.

Shadowplay captures things differently. I've spoken to Jim about implementing some of nVidia's tech into his game capture to reduce the performance hit, but he has more pressing matters to attend to. If it ever works, we might have a much better game capture scenario. Never forget: Your game might hate OBS' game capture methods, and you'll get an inordinately large performance hit by using game capture. A great example is Dark Souls 2 (at least on SLI systems using GeDoSaTo). Programs like Playclaw 5 and OBS' game capture absolutely demolish its framerate. Tons and tons of leftover CPU power but the game barely runs above 30fps when being grabbed. I had to resort to monitor capture for it.