@feld @darth @RTheren
Also, I was surprised at the CPU decrease by switching from a dual Intel gige nic to a Chelsio T520 10gige w/ a 1000base-t SFP module.
Really, it's likely a combination of those ethernet drivers being slow, the ethernet hardware itself being slow, and that there aren't "cheap" arm boards that have half decent CPU performance. (10gig cards can do multiple queues, which very few gige nics can do, or if they can, drivers don't support it, or support it poorly).