A 570 will be a horrible experience. My 590 without SLI enabled was a slide show, and even with SLI it was a stuttery mess. Aside from the lack of power, the 500 series also lack sufficient VRAM. Going from the 590 to a 970 made a ridiculously huge difference. Sub 30fps with stutters on the 590 at any setting to averaging around 75-90fps in a mostly full hanger with the 970 at 1600p very high setting. (350R, M50, Connie Phoenix, Mustang Delta, Super Hornet, Cutlass Red.) AC botless sim went from a mess where the framerates would bounce from barely playable to headache inducing on the 590 to silky 60+ on the 970. (A match with people or bots I haven't done yet on the 970, and didn't dare try with the 590.)
I was going to wait until later in the year for the rumored die shrink and do a full system replacement for my aging machine. (i7-920 @ 3.5, 12GB RAM - originally with a freaking GTX 295 before the 590) With the new details on Pascale though, I decided I'll put that off to 2016. I didn't have the patience to wait potentially over another year to make SC playable, so I decided the 970 was a good stop gap measure. Pleasantly surprised so far with the results so far. The real test will be in a game with more than one ship flying around - both for the card and my old CPU. Still, that old CPU has served me very well over the years.