I have an Anker usb 3.0 hub: https://www.amazon.com/gp/product/B089M7WSHM/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1
I have a Sandisk Extreme Go: https://www.amazon.com/gp/product/B01NARBPI7/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1
I'm using a 12W apple power brick (I also tested with a 29W).
The same stick on my Nvidia shield using Disk Speed Test shows over 100MB/sec for both read and write. On the Chromecast its showing 36MB/25MB. I tried a few other USB 3.0 sticks I had laying around and also got low numbers.
So I installed "USB Host Test" and it shows the Sandisk Extreme as "USB 2.1" not 3.x.
Does the Chromecast not support USB 3.x storage? The Anker is a USB 3.0 hub. Any thoughts?