On the contrary, having bad uplink on what should be symmetrical (even if half duplex in the case of Wi-Fi) is something that will kill your performance. Upload is just as important as the download.
Have a source for that? If true, every cable internet customer in the US would have their perfomance killed as you put it. Comcast, TWC, Charter, Suddenlink etc etc, none of them offer up speeds that are anywhere close to down speeds.
Well I have had Fios for about 2 months now. And here are 2 screencaptures I did on speedtest.net. The first is from 2 days after starting service. The second was from about an hour ago:
2 days after starting service:
It seems I've gone back to having DSL.
It is possible that something is causing interference on your wifi.
Or an issue across Internet.
Run test to speedtest.verizon.net.
That will test your speed within the Verizon network (which is all Verizon can control).
If that still gives poor performance, you need to check your wifi.
If you have an android device, download an app called wifi analyzer.
If can show you a lot of info about your wifi performance.
If you don't, try logging in to router and chaning channel.
Default is usually auto which may not give optimum performance.
Try changing channels to see if peformance improves.
What model router do you have?
FYI FiOS does not use modems. The device you are referring to is a router.