And for Gmail specifically you might want to look at the mbsync option PipelineDepth As noted in the .mbsyncrc gist: > The value is "used to limit average ban

And for Gmail specifically you might want to look at the mbsync option PipelineDepth As noted in the .mbsyncrc gist: > The value is "used to limit average bandwidth consumption (GMail may require this if you have a very fast connection)." Turns out the same is true for iCloud. There's probably some optimized value greater than "1" that can be used, but this works for me. I actually have it set to 5 now.