Ask HN: Why Is Speedtest Upload Test Disrupting Pings?

We have been recently blessed with Gigabit Fiber connection from AT&amp;T. In my unscientific attempt to gauge connection stability I usually run 100 DNS pings and SpeedTest - all via latest Win 10 connected directly to router by short Cat 6 (gigabit) ethernet cable.<p>Today I noticed serious slowdowns in Ping but ONLY during Upload portion of the Speedtest, which itself reported 700mb&#x2F;s. While 940 mb&#x2F;s Download test has almost no impact on ping timing. Any idea what may explain this?<p>Reply from 8.8.8.8: bytes=32 time=3ms TTL=53 Reply from 8.8.8.8: bytes=32 time=4ms TTL=53 Reply from 8.8.8.8: bytes=32 time=4ms TTL=53 Reply from 8.8.8.8: bytes=32 time=5ms TTL=53 Reply from 8.8.8.8: bytes=32 time=5ms TTL=53 Reply from 8.8.8.8: bytes=32 time=4ms TTL=53 Reply from 8.8.8.8: bytes=32 time=6ms TTL=53 Reply from 8.8.8.8: bytes=32 time=3ms TTL=53 Reply from 8.8.8.8: bytes=32 time=3ms TTL=53 Reply from 8.8.8.8: bytes=32 time=82ms TTL=53 Reply from 8.8.8.8: bytes=32 time=165ms TTL=53 Reply from 8.8.8.8: bytes=32 time=222ms TTL=53 Reply from 8.8.8.8: bytes=32 time=266ms TTL=53 Reply from 8.8.8.8: bytes=32 time=285ms TTL=53 Reply from 8.8.8.8: bytes=32 time=303ms TTL=53 Reply from 8.8.8.8: bytes=32 time=321ms TTL=53 Reply from 8.8.8.8: bytes=32 time=337ms TTL=53 Reply from 8.8.8.8: bytes=32 time=352ms TTL=53 Reply from 8.8.8.8: bytes=32 time=368ms TTL=53 Reply from 8.8.8.8: bytes=32 time=379ms TTL=53 Reply from 8.8.8.8: bytes=32 time=389ms TTL=53 Reply from 8.8.8.8: bytes=32 time=282ms TTL=53 Reply from 8.8.8.8: bytes=32 time=3ms TTL=53 Reply from 8.8.8.8: bytes=32 time=3ms TTL=53 Reply from 8.8.8.8: bytes=32 time=3ms TTL=53 Reply from 8.8.8.8: bytes=32 time=3ms TTL=53<p>It starts around same time as speedtest started, and at the end you can see &quot;normal&quot; results when speedtest is finished. You can see that download test reported higher speed and had barely any impact on ping test timings.