I'm playing netplay with a friend in texas, the other three of us are in the southeast. The first couple of nights netplay was working without a hitch, but now for some reason he gets huge ping spikes in the 300s when his average is ~40. His pc is better than mine, he lags no where else on any other game, we've tried switching hosts etc. What could be the problem here
Ping spikes are out of Dolphin's control, it's just telling you what the ping is.
You can try resetting the router of the player that is having ping spikes as sometimes they do act up, but, otherwise, it's up to them to figure out why their internet is having trouble.
My understanding is that the ping displayed in Dolphin is not solely connection related but takes in a bunch of other things into account. His internet is fine. Steady 20ms on other games and 120mbps download. It's not connection related. Also when we started playing together 2 nights ago, his ping was steady and there were no spikes.
Then what exactly is the ping taking into account that we don't know about? In most games, small spikes won't be noticeable because they're not in lockstep.