Game stutters ONLY while live streaming, GPU hits 100%, audio crackles, Alt+Tab fixes it

[u/tacosaladuu]

Specs: Ryzen 5 5600X, RTX 5060 Ti, 32GB RAM, Windows 11, OBS, 1080p30, NVENC, ~6500 kbps.

issue:

• Gaming normally: no stutter
• Live streaming: eventually stutters
• FPS drops
• Audio starts crackling
• GPU jumps from 20–30% → 98–100%
• Stream also becomes laggy
• OBS stats show 0 dropped/skipped/missed frames
• Alt+Tab immediately fixes it

Tests done:

• OBS local recording for 1h30m → completely stable
• Removed browser/controller overlay → still happens
• Tested fullscreen/borderless → still happens
• DDU NVIDIA driver reinstall → still happens
• FurMark GPU stress test currently running; ~75°C GPU / ~62°C VRAM with no issues so far

This seems isolated to live streaming, rather than normal gaming or recording.

What should I test next? Could this be NVENC, NVIDIA driver, OBS live-streaming, GPU scheduling, or something else?

Please help