[2019] What should I upgrade on my rig?

2 hours ago, GSutt said:

Intel i5-6600 @ 3.30Ghz

16gb Ram

Gtx 970 SSC Gpu

The GPU is weaker so you should go for that first. I personally like buying one tier down from the best at a minimum. Reasons: The best is much more expensive and one tier down is still relevant but not full original price. 

Then go for CPU. RAM size you have is good but ddr matters too. 

You also might need to look if your MOBO is new enough to support your new toys when you upgrade so heads up on that. Use PCpartpicker as suggested above. Saves you lots of hassle and research.