I have installed 2 keystone plates in two rooms with wires running through my attic for Ethernet, HDMI, and coaxil. I am awaiting delivery of the last 2 cables, the total run length will be about 75 feet 3x25 for HDMI.
I want to know, will this be to long of a run for HDMI cable to get 1080p from my PC(bedroom) to HDTV(living room)?
HDMI will officially go 50 feet, but i have seen cases where it will go more with a well shielded cable. Just keep it away from power, speaker, and any other sort of electrical wires, and you should be ok.