[Sebastian Alvarez] “The card comes with a mini HDMI output, but the cable that comes with it is not long enough to reach the TV. Still, I’m not sure that it would make a difference”
You can try to extend your mini HDMI cable by using a HDMI Female to Female adapter and another short HDMI cable, I don’t know if that would cure your problem but sometimes DVI to HDMI can cause problems, also since the problem is cyclic it possibly could be a memory problem either in the computer or on the video card, in the computer you could run a memory routine over night to check the memory, but for the card the best way is substitution.