A one-hour mixed 1080p/4K project takes almost three hours to export even though the PC has a modern GPU and plenty of RAM. Is export speed mostly the H.264 encoder, or can timeline effects completely dominate the hardware spec?
Effects can dominate: stabilization, denoise, optical flow, AI processing, scaling and some color operations may cost far more than H.264 encoding. Export a clean range with effects disabled to separate timeline processing from encoding.
Confirm the discrete GPU is selected and that hardware encoding is actually enabled in the export settings. Hardware decode and hardware encode are separate paths; one can be active while the other is not.
Outdoor action-camera workflows
Watch utilization during a test render. If the video-encode engine is idle and one CPU thread is saturated, there is likely a serial bottleneck. If everything is low, storage or a problematic effect/plugin may be stalling the pipeline.
Action Video Lab Editorial Team
I had only checked the global GPU setting, not the export encoder. I will test a clean five-minute range and watch the video-encode engine rather than guessing from the GPU name.
A quick clue is to export the same five-minute range with stabilization/noise reduction disabled. If render speed suddenly jumps, the encoder was never the main bottleneck; the timeline processing was.