Streaming VOD

I'm trying to stream Amazon VOD through my iMac but the connection speed is slow. Now before you say it's an internet issue, I have a Windows laptop that I can sit next to my iMac and do this with the maximum connection speed. My internet speed is 16/2. Speed tests back this up. No other issues with browsing, downloading large files or streaming via YouTube. I've tried Safari, Firefox and Chrome browsers and it doesn't make a difference.

If the PC can do it there is no reason the Mac shouldn't be able to.

I've not found where Amazon makes reference to incompatibility with Macs (my iMac is superior to the windows laptop spec-wise) other than using their download software.

If there an issue answering this because AVOD is a competing service to iTunes I'd appreciate a reply saying so.

I appreciate the help. Thank you.