ZxFragz

I think a 580 is probably your best bet for value. 
At the end of the day, it depends what your going to be playing. Overwatch? I've seen plenty of benchmarks with budget cpus like the 2600x crack a solid 100fps on ultra settings. Siege? You'll get your desired 75hz. As long as your looking to stay at 1080p and not playing the most demanding of titles at max settings, the 580 will be a great card for you and certainly be worth the money. 

Also for a more accurate perspective look up 580 benchmarks on Youtube. Better yet, see if any include your CPU specifically for a more reliable expectation.

Thank you immensely. Very informative and has cleared up the confusion for me.

Thanks for the confirmation. I'm looking to play at moderate to high settings, but sacrificing a few settings for better performance won't kill me.
 
I'll have it upgraded before 2020 is out anyways. 
 
Speaking of which, what sort of 250-300 pound care would you recommend the upgrade too. 1660ti? 1060? 2060? What do you think?