Q:

Screen resolution of MacBook Pro Retina

I have a MacBook Pro 13" Retina-display (Late 2013 model)
I recently bought a very cheap HDMI cable to plug it on my tv in my room (for Screen Mirroring and sometimes, Screen extend). Since it's cheap, I'm quite worried on a possible effect it would bring to my MacBook's resolution or display or maybe performance or at least, something.  
Will it ruin my MacBook in any sort in the long run? Should I just forgo the cheap HDMI and invest on a better quality albeit being a bit more expensive, or Thunderbolt, perhaps? (Never tried Thunderbolt)

A:

No, if a cheap cable works between your TV and Mac you won't find an expensive cable works any better, and a cheap cable isn't going to have any effect of your Mac's longevity. Use it and enjoy the fact you could have paid so much more for a cable and gained nothing at all ;-)
Additionally, using a Thunderbolt/mini-DisplayPort adapter uses the same signalling protocols as HDMI and the output to your TV would be exactly the same.

