Classic Warcraft 3 periodic lag spikes

I can’t get through even a 15 minute custom game [dota] without 2+ lag spikes I’ve had dell run tests on my computer to check of overheating and run and internet speed test and everything checks out. I’ve tried playing on both us servers. I’ve tried setting the graphics API to direct 3d9. I have no verifiable pattern as to when the spikes happen. I’ll be playing normally and then everything gets stuck for a few seconds and then “jumps” to where it should be.