I spent top dollar for the cable I have But I guess I could get another one. The resolution is set at 720.
Spending top dollar for a cable does not mean you received a top quality cable.
You are best off always getting cables from dealers that are well known to provide top quality cables like:Monoprice
orBlue Jeans Cable
For example Monoprice has a top quality 6 ft. HDMI cable
for $6.90 or less. (About 11.08 with shipping for a single cable but that per cable price goes down if you order more than one.)
I order all my cables from Monoprice and I have yet to be disappointed.
As far as the issue you have it really does sound like a cable or HDMI port problem so trying a different port and/or cable could very well resolve the problem.