It not the cables this can be caused by the video drivers over heating I have gone through several video drivers already since I always tend to over clock my pc playing games so I would say check the cards and the power supply that is another reason why it can be flickering not enough mhz getting to it in the last 2 years i went through 2 power supplys and 3 video cards since i normally leave my computer on all the time or play game on extreme settings along with streaming game content over twitch.