Lesson 4.1 - CPU Encoding on RTX GPU
Mistake 1: CPU Encoding on RTX GPU. Using x264 (CPU) encoding when an NVIDIA RTX GPU with NVENC is available.
The pattern: streamer installs OBS. Default encoder is x264 (CPU-based). Streamer doesn't change it. Encoding burns 30-50% of CPU during streams. Game performance drops. Stream drops frames during high-action moments.
Why this happens:
- OBS defaults to x264 because it works on every GPU
- Many guides reference x264 because it's universal
- Streamers don't realize NVENC is significantly better and free with their existing hardware
The performance difference:
- x264 software encoding: uses 30-50% of CPU. Quality good. Performance impact significant on game-streaming.
- NVENC (NVIDIA RTX cards): uses ~0% of CPU. Quality comparable or better than x264 medium preset. No performance impact on games.
The fix:
- OBS → Settings → Output → Streaming tab
- Encoder dropdown: select "NVIDIA NVENC HEVC" (or H.264)
- Preset: P5 (Quality) or P6 (Slower)
- Tuning: High Quality
- Apply and run a test stream
How to verify NVENC is working:
- Check Windows Task Manager during streaming
- GPU usage should show NVENC encoder activity
- CPU usage should be dramatically lower than before the switch
Free performance lift. Most streamers can implement this in 60 seconds.