That's strange. My results are so consistent (65ms or 66ms), it's eerie. Could be something about this network (office).

Does it make any difference if you try to limit Firefox background connections? See: How to stop Firefox from making automatic connections.

So far, I've disabled automatic browser and search engine updates, DNS and Link Prefecting, disabled Firefox data collection in settings, and disabled "Send Video to Device".

I kind of don't want to disable the rest in the article because I'm skeptical of safety, but all of this does not return a consistent ping.

Sorry, I should have pointed you to the captive portal (Network Detection) setting as someone reported here that it may fire very frequently.

You talking about this in the Firefox Configs? It's already false.

Could it be an extension? If you haven't already, could you test in Firefox's Safe Mode? In its Safe Mode, Firefox temporarily deactivates extensions, hardware acceleration, any userChrome.css/userContent.css files, and some other advanced features to help you assess whether these are causing the problem.

If Firefox is not running: Hold down the Shift key when starting Firefox. (On Mac, hold down the option/alt key instead of the Shift key.)

If Firefox is running: You can restart Firefox in Safe Mode using either:

• "3-bar" menu button > "?" Help button > Restart with Add-ons Disabled
• (menu bar) Help menu > Restart with Add-ons Disabled

and OK the restart.

Both scenarios: A small dialog should appear. Click "Start in Safe Mode" (not Refresh).

Any improvement?

Im having the exact same Problem. Ping Spikes well into the 2000ms, with it comes huge bandwith losses and also it affects the whole system (Windows Update etc). I even suspect that its affecting my router since the whole network slows down as long as im using FF on that desktop.

Images below, Nperf Speedtest (any other Speedtest will result in the same loss, just Nperf is showing it while other speedtests just freeze and suddenly start again at top speed), second picture is the very same test roughly 2 minutes later made with FF closed using MS Edge (latest stable). Last is a Ping -t using CMD to my router.

I already have done: -without addons -refresh -clean uninstal (with deleting folders in appdata) and reinstal. Nothing helped, but its only happening with Firefox.

Hi Tobi, do you want to experiment with the settings listed in the following article: How to stop Firefox from making automatic connections.

jscher2000 said

Hi Tobi, do you want to experiment with the settings listed in the following article: How to stop Firefox from making automatic connections.

Hi, thx for the answer. I decided to do my own thread, since i didnt know if such an old question is still showed high up.

https://support.mozilla.org/questions/1270256

If thats not wanted, i certainly will (or ask for) delete it.

Edit: I tried these suggestions, no change in the behavior.