Question / Help NVENC settings on GTX 1060 6GB

[Niphrentil]

Hey forum, here's my issue...

I recently upgraded my internet connection and I'm now running a 5MB upload speed and trying to run a smooth, 720p60fps stream. Thing is that my 2nd generation CPU (i7 - 2600K) isn't too fond of that and gives me framedrops even at veryfast preset.

Now, I looked around the internet as to why OBS doesn't let me use QuickSync which would, in theory, solve my problem but Windows 10 don't use the Intel HD Graphics chips of CPU's older than 4th generation. So, what's left is to use my GPU's NVENC encoder.

Now, here's the issue. I read tons of guides and tried quite a few different settings to learn how this encoder behaves and I think I got it to where it pleases my needs. The settings I'm using are:
Rate Control: CBR
Bitrate: 3500
Keyframe interval: 0
Preset: High Performance
Profile: high
Level: auto

Now, when I use these settings to record stuff with "Use stream encoder", the output is just fine, very good quality 720p 60fps video, and my games run smooth as hell, most of them at way over 100 fps (i.e. League, Fortnite, Diablo 3)

But when I click the start streaming button, everything goes out the window, I get frame drops as high as 50% right at the get go and keeps dropping to lower frames the more I stream (here's a clip of a test, I started a game at ~60 fps and at the time I closed OBS because the game was unplayable I was at ~25: https://www.twitch.tv/videos/252915254 ) and, for some weird reason, my CPU Load still shoot up to 80% (while, on recordings, it idled to ~30%).

What am I missing here?

PC Specs:
CPU: i7 2600K
GPU: GTX 1060 6GB
RAM: 24GB (2x8GB, 2x4GB, both Dual Channel)
SSD: 64GB (OS exclusive)
Net: 50 Down/5 Up

Latest OBS Log File:

 

[koala]

There is no recording/streaming attempt in your log file. Restart OBS after doing a multi-minute recording and upload the "last" logfile. This way, you have a complete log.

 

[Niphrentil]

OK, don't know what happend with the log file, it was the log file of the test session I took the clip from, so I couldn't not have been streaming. Anyway, I did one more, Recorded one half, streamed the other half (changed the encoder profile from high to main in case anything changed but nope). Same situation. While recording I had 70-90 fps / CPU at ~40%, while streaming fps drop to below 60 down to ~30 (unacceptable for 60fps streaming) and CPU shot up to 60+%.
Streamed part:
https://www.twitch.tv/videos/252938239

Screenshots of recorded part + log file:

 

[Niphrentil]

Bump

Anyone that can help? It's been 3 days now and I can't figure out what's wrong.

 

[Niphrentil]

The weirdest part of it all is that, even after the fps eventually drop down to unplayable levels (15-20 fps), even if I close the stream, even if I turn off ANY other software running at the moment (OBS, Browsers, music players, support software etc) the fps STILL remain at these levels! Even if I lower the in game graphics, nothing changes, it's like something else is hogging all my PC resources and I can't find out what it is. Only way I found to reset the PC to the previous state is to actually reboot the PC!

This happens ONLY when I'm trying to stream, recording works just fine!!

Please, if anyone has ANY idea what's going on, I'd much appreciate the help. This issue is driving me nuts!

P.S. I just found out today that the same issue persists even with CPU encoding (so it may not be an NVENC thing altogether), I used the exact same settings I used for a couple of years of day-by-day streaming (720p, 20fps, 1000 bitrate) and I STILL got the same issue. Started the stream with ~80 fps, half an hour later it had dropped to ~30. Even closing the game down and launching a different game after I turnned off streaming didn't do anything, On a game I usually get 150+ fps when I'm playing offstream I got 30-40fps while no other software was running. Again, had to reboot my PC to get the games to working normally again... :/

 

[Niphrentil]

Bump with more info.

I noticed that games running on Unreal Engine are unaffected by the formentioned prerformance drop. UE games like Fortnite or Tekken7 run smoothly. Also, other nvidia-backend based games like Lords of the Fallen seem to be unaffected. Games running other engines like EA's Frostbite (Need for Speed, Mass Effect Andromeda) or custom developed graphics engines (like League of Legends, Diablo 3 or Ubisoft's Anvil engine for For Honor) all show massive performance drops after a few minutes of streaming.

I thought it would be a drivers issue but the performance of said games doesn't reset with a driver update (which it should if it was a driver issue), only a PC reboot can bring the fps back to normal values (only to drop again if I start streaming).

P.S. In order to check if it was an OBS Studio issue, I dug up my old OBS Classic platform and tried to stream from that. Once again, same issue. Recording works perfect, streaming f*cks everything up. So, it's not an OBS Studio specific issue. It's just that something happens to my PC when I start streaming and I can't figure out what.

P.S.2 I just... I don't even... Pffffff....