If your smart TV isn't looking or sounding its best, the fix might not be a new TV but a few simple HDMI changes. Related I Always Run These 6 Tests Before Buying a Used Smart TV You can never be 100 percent sure, but running these checks should help you catch most smart TV issues. If your TV and connected device (like a console or Blu-ray player) support HDMI 2.1, you'll want a Premium Certified or Ultra High Speed HDMI cable. Justin Duino / MakeUseOfMany TVs let you optimize each HDMI port for the type of device you connect. While you are at it, you could also explore more deeply to fix smart TV settings you might have set up incorrectly.