I've just bought an external display (Dell U2419H). I'm aware that since it's not 4k it won't look as good as the retina display, but should I connect directly via HDMI or should I buy an adapter?? I'm currently connecting it directly by HDMI, but the image doesn't look much sharp and I'm wondering If it will help to buy this adapter: https://www.apple.com/us_smb_83039/shop/product/HHLN2ZM/B/belkin-4k-mini-displayport-to-hdmi-adapter My display resolution options on system preferences settings are: 1600x900; 1080p; 1080i and 720p. I've read that this means the Macbook is recognizing the display as a TV, not a monitor, so I'm also wondering how to fix this. Thanks.