[throwaway3563]

The write load will be nearly constant but it won’t be sequential. The host device is going to have to update file system data structures periodically as it is writing the video stream; those structures will be at various different places on the drive. So the write load will look like 99% sequential, 1% random. That small amount of random writes in a non-contiguous stream is enough to cause SMR-related rewrite stuttering, especially since with DMSMR the host has no idea how logical blocks presented by the drive map to SMR regions.