Low CPU Usage - Can't Raise Frames Higher than 48

[MarcosWithAnOh]

Hi there!

I want to start this off by saying we're running a slightly more unique setup. We have a three PC setup as my roommate and I stream together. We run each of our own machines directly into the third machine which has 2 Elgato internal capture cards.

On our main scene we use 4 video sources and 1 media source. The rest of the layout is browser sources. Videos are custom resolution of 1280x720 and main feed is downscaled to 720p. We can't get 60FPS no matter what I've tried. Though wherever we're live, CPU usage is barely peaking over 25%.

Is there nothing I can truly do because of the amount of video sources we're using, or are there other options I can try? If more information is needed, let me know what I can grab and I'll do so. Appreciate any help on this!

 

[FerretBomb]

Post a logfile from a live streaming or recording session where the issue occurred. We really do need one to start troubleshooting, why it asks for one to be attached when opening a thread in the Support section. :)

You'll also want to download and run a utility called GPU-Z and make sure your GPU is running in x16 mode. Low framerates usually mean that the GPU is being over-taxed (OBS *requires* a discrete GPU), but it's possible with two cap cards and two video sources, plus an unknown number of browser sources needing to all update to VRAM, you might potentially be running into PCIe bus bandwidth choke somewhere, depending on the lanes available, how they're split, and so on.

We'll be able to tell more once we look over the logfile.

 

[MarcosWithAnOh]

Totally sorry about that! Wasn't sure in this specific case if the log file would have helped, but by default it helps at least give a better insight to what was going on. I've attached the log files from the day of our stream when we had to restart multiple times.

I'm not sure if I read this 100% correct, but it does appear to be running in x16. Image for verification.

 

[MarcosWithAnOh]

Bump and more info(if it helps). We're using two Elgato HD60 Internal Capture Cards and two Logitech c920 webcams.

 

[TryHD]

Your CPU is to slow, upgrade your CPU to AMD 3900x or better, or upgrade your GPU to a nvidia 1650 super or better and use NVENC instead of x264 for encoding.

 

[carlmmii]

CPU isn't the issue. That should have absolutely no problem handling 4 1280x720 capture feeds at 60fps.

It would be helpful to have a log file from a 60fps attempt, as that's where you're encountering major issues. But, even the last log file you posted has a significant amount of rendering lag with absolutely no encoding lag, so it's a pretty safe bet that this is entirely a GPU bottleneck for rendering the scene.

The GPU is running in PCIe 2.0 mode, which is the first red flag. Is the GPU installed in the top-most slot? Ideally, you should be running in 3.0x16 mode, but depending on the motherboard you may be limited to 3.0x8 as you also have 2 PCIe capture cards. Check your motherboard manual for the preferred configuration. The biggest thing is not running off the chipset PCIe lanes, as that will be fighting for bandwidth priority with all other IO devices in your system.

Also, was the GPU-Z screenshot taken with OBS running?

 

[MarcosWithAnOh]

Hey, thank you for providing a bit more insight with this. I manually set the Elgato in Game Capture HD to capture at 720p rather than 1080p and this helped a bit. That being said out of nowhere while things are running smooth, the frames just get cut hard. Here is the recent log from that stream - https://obsproject.com/logs/I-zPnlR-mdLmsET_

Here's attached our CPU-Z stuff so you can see what we're running in our third system.

 

[MarcosWithAnOh]

are the elgatos are on the same USB hub device ?

Two Elgato USB 3.0 Devices on one Computer - Two USB 3.0 Root Hubs Needed.

If you want to use two Elgato USB 3.0 Devices on one computer at the same time, your computer will need to have two separate USB 3.0 Root Hubs or Host Controllers. Elgato USB 3.0 Devices include: E...

help.elgato.com

They're not the USB versions. All internal.

 

[MarcosWithAnOh]

Update with active GPU-Z settings.

 

[carlmmii]

And that's with OBS running?

 

[MarcosWithAnOh]

Yes, but right now we had to lower fps to 48 because it started dropping hard.

 

[carlmmii]

Sent a DM, but yeah... try putting the GPU in the top slot. GPU-Z is reporting that your GPU is operating in 2.0 x1 mode, which is severely limiting the bandwidth available, which is causing the rendering lag because it just can't get all the data it needs to composite the frames within the necessary 16ms frame time.