If you can buffer it, and it still lags, it's not your internet connection. I can load it up fine, but at 4k, I get frame drops. Fine at 720, 1080, and 1440 HD res, but at 4k it's "catching". Not surprising considering I'm using a 6 year old MacBook with a gfx card that was never designed for 4k (native res of 1440)