I feel your pain. I play Guild Wars 2 and get the same random spikes that make me unable to defend myself. It's very annoying and the game become unplayable. We had outages in my area and they say my net is impaired. I had a nice window for a few hours to play normal, but now it's all downhill again. I get 200+mbps on speed tests, now its like 9-17mbps. Bummer.