Which should I upgrade first, cpu or gpu?

Hey guys, I right now have an FX-6300 and a GTX 950. I want to upgrade both of them but I'm wondering if I should upgrade the FX-6300 to an i5-4690k first or rather the GTX 950 to a 970, my concern is that 6300 would bottleneck the 970 if it isn't changed out first. Anybody have any advice?