Routing tends to vary but westbound is always heading north towards Alaska before turning towards Japan and then onto Taiwan. Sometimes, they hit north of Japan and crossing Mainland Japan before exciting through Miyazaki, but then sometimes they take a bit southern route along the coastline. I will say that connections get weaker after passing Alaska and will not gain strength until it gets closer to Japan and Taiwan.

The return from TPE to NYC really varies day to day - sometimes they go northward towards Alaska/Canada/NYC, but then it can go south and enter US through Seattle/Vancouver and then typical Pacific NW to New York routing.

But my rule of thumb about airline Wi-Fi on international flights is that they are still mostly slow and you can't rely it to stream video or download large file (maybe a podcast but nothing major). Things get better when less people use it in mid-flight. However I will not rely it for work.

I paid for WiFi on my LAX to TPE flight in late December and our routing was close to Hawaii and things really slowed after passing Hawaii and did not get stronger as we got closer to Okinawa. EVA Air WiFi is not too bad and is at least better than Starlux, but Cathay's WiFi is better.

Carfield