Ping spikes and unstable latency

Ping spikes and unstable latency cannot be assessed from a single Mbps number. Throughput, latency, jitter and packet loss describe different properties, while Wi-Fi, Ethernet, competing devices, VPNs, routing and the test server all affect results. High throughput can coexist with poor latency under load.

How to find the bottleneck

Separate the LAN from the ISP path: check signal or cable, then ping while idle and under transfer, then throughput. Repeat measurements under controlled conditions. A problem that occurs only in the evening, only through a VPN, or only toward one destination points to different bottlenecks.

The detail that matters

A useful latency series records more than an average: inspect median, high percentiles, jitter and packet loss over time. Short Wi-Fi airtime contention can create spikes without changing ISP bandwidth, while sustained latency growth during uploads can point toward queueing or bufferbloat. For a control measurement, use 2ip ping and traceroute.