OMG!
Thank you all so much!
High settings are not necessary.
I've been playing on a potato, (2014 MacBook pro), when I can and I've developed some really bad tendonitis in my right wrist from work the past two years so I can usually only play for a couple of hours before I have to start popping Ibuprofen to keep going which is no fun so this machine would just be for the occasional grind on the weekends.
I think repasting is a great suggestion that I totally would not have thought of by the way so thank you for that suggestion!
In total, I was given 3 GTX 780s and 1 GTX 770. The 780s are ASUS Poseidons that were hooked up via SLI without the water-cooling initially which inevitably led to 1 or 2 overheating. The friend that gave them to me wasn't sure which cards were bad, he just knew 2 of the 4 were no good. Im hoping its the 770 and 1, 780 but I won't know until I start plugging them into the machine. ?
Im super grateful for all your time and help and appreciate the feedback!