You're correct AM3+ CPU's won't fit. The GTX 970 could work tho. That motherboard's PCI-E 2.0 x16 is fine even though the card supports PCI-E 3.0, the real-world difference is negligible. The fastest CPU you could fit on that board would be the AMD A10 6800k. That CPU would theoretically be a bottleneck in some situations, but actual performance is going to vary from title to title.