I ran FurMark 1080p preset using the same settings and noticed a consistent FPS difference depending on whether the iGPU is enabled or disabled.
• iGPU enabled: 134–135 FPS
• iGPU disabled: 114–115 FPS
Nothing else was changed between the tests. Same resolution, same preset, same temps, same background apps.
Specs:
GPU: RX 6600
CPU: Ryzen 5 5600GT