What's causing my lag spikes?
A speed test averages spikes away. This records your ping ten times a second, then reads the pattern: spikes on a strict beat come from something on a timer, random bursts from other traffic or Wi-Fi interference.
Spike finder
Sends about ten tiny requests a second and records how long each takes. Keep this tab in front and play or call as usual on this device, or leave it idle.
Spikes only when someone else is downloading? That's bufferbloat: the Smart Queue assistant fixes it.