
Strange browser and app dependant results.
I've just had FTTP installed (in the UK, Openreach infrastructure and Vodafone as the ISP). My contract states 500/67 down/up.
When I test this using the Speedtest.net website on Safari (I'm on a Macbook) this is what I get, consistently, repeatably, both on WiFi and when I plug in using a USB-C / Ethernet adaptor.
Other approaches - much more confusing.
Same hardware - Arc and Firefox and Chrome - download never gets above 370, but all pretty consistent.
Speedtest app: also ~370 download.
It's upload that's really strange - all methods other than Safari show a very severe drop off during the test - I start with a peak of ~65, and then it drops off rapidly, finishing off at the end of the test period at barely 1Mb, sometimes even zero.
I can understand some variation between browsers for download speed - they will have different SW stacks, but what in particular is causing the upload drop-off during the test, especially on the speedtest app, which I understood was the 'gold standard' on any platform?
(Can't seem to add a screenshot......)