Does 1080p HDMI Cables support a 720p HDTV?

Question

Or do I have to buy different HDMI cables...

Answer 1

Usually the cheapest hdmi cable you can find will work for everything from SD resolutions to 1080p. However you need better shielding (which will only be the case on more expensive cables) for longer distances. The distance you can cover with a cheap hdmi cable might be higher for 720p than for 1080p, but in general if some manufacturer 'argues' by it's products or commercials that you need more expensive cables for 1080p in any case no matter how short the distance between the devices he's just trying to cheat you. If it's just for 2 meters or 2,5 meters all hdmi cables will work for all resolutions. For long cables (more than five meters) you might look for better ones to get a reliable connection no matter what resolution you use and for distances of 10 to 15 meters you will need really good cables.

Also with HDMI 1.3 there was a new (smaller) plug type defined. Some companies might cheat you in believing these cables are neccessary for a HDMI 1.3 connection. That's simply not true. The new plug type is an alternative primarily meant for portable devices and if a device has such a connector it's definitely a HDMI 1.3 connectors, but that does not mean the larger connectors can't be HDMI 1.3. Also you will find cables claiming to be HDMI 1.3 cables. (This is why I bring this 1.3 topic up now) Actually it is true, that HDMI 1.3 allows for higher transfer rates which may (depending on the distance to cover) require better shielded cables ... however: Any older hdmi cable that is better shielded than the really cheap stuff will work, too.

Well, to answer your question directly (which I just noticed I didn't do yet :D ): If a hdmi cable works for 1080p it will work for all lower resolutions.

Answer 2

yes,

supports multiple resolutions like 480p, 720p, 1080i and 1080p

and any HDMI cable can support 720p...