Question / Help Quick help with performance while recording

[Luiz Silveira]

Hi there,

Sorry for the simple question. I've been reading about the settings and whatnot for months, and I've read and watched a number of guides. But I'm having difficulties fine-tuning the recording settings.

I want to record (not broadcast, unfortunately) iRacing. I can run it with 100+ fps no prob, with my Radeon 7770 GPU being highly used (close to 100%) and my CPU being used much less (around 90% on one core, 70% on another, and very low on the other two). It's an i5 4690k.

I'm using x264 and not Quick Sync. The reason is, once I enabled the CPU's integrated vid. card I lost a lot of performance with iRacing. So I went back on that. Then I have CBR unticked, quality 9, max bitrate at 3000 and buffer at 0. My resolution is 1600x900 and I'm downscaling to 720p with "good"(medium) detail.

On the Advanced ones I have x264 preset on "superfast", CFR, and custom setting "crf=22".

I had started with much higher settings (quality 10, higher bitrate, "veryfast", "crf=15", no downscale) but every time I turn OBS on to record I lose a lot of fps and I start to get stutters in-game.

I've heard and read that OBS is CPU bound so I went on trying to improve that. My CPU is 3.5Ghz, with the turbo should go to 3.7 stock. I've OCd it to 4.0Ghz (I know, nothing spectacular but still) and zero difference. So I tried lowering the settings to the ones I mentioned, still no difference.

Would you have any advice or anything else I could try?

Much appreciated.

 

[Harold]

Use the recording guide's settings EXACTLY.

When using crf-based bitrate selection, what would normally be quality loss that comes from using a faster-sounding preset is instead increased bitrate and file size.

 

[Luiz Silveira]

Use the recording guide's settings EXACTLY.

When using crf-based bitrate selection, what would normally be quality loss that comes from using a faster-sounding preset is instead increased bitrate and file size.

Thanks. I had tried it, and just tried it again. FPS drops from 110 to 90. Not that I was expecting "loss-less" recording but still. That means that when the game is pushing it (several cars around etc.) and fps would normally drop to ~80 I'll get stutters and 60fps instead...

 

[Sapiens]

You should probably be limiting the game's FPS anyway, e.g. to your monitor's refresh rate, so your CPU/GPU resources aren't all getting sucked up rendering a bunch of extra frames that aren't displayed.

 

[Luiz Silveira]

You should probably be limiting the game's FPS anyway, e.g. to your monitor's refresh rate, so your CPU/GPU resources aren't all getting sucked up rendering a bunch of extra frames that aren't displayed.

Yeah, I do limit them at 84 or 94 depending on situation. Going any lower I start to notice things are less smooth for some reason.

Unfortunately I have no option to use vsync or similar, as I run it windowed.