slow pci-express

So I've recently had my GTX 970 give out on me. Not sure why, there wasn't any visible damage to it. So I've since swapped back to my old card the GTX 750. I initially installed it in my mobo's PCI 2.0 slot forgetting I had a PCI 3.0 express slot for my video card. Now in the 2.0 it worked...

I have a SSD and a mechanical both nearing the 4 year mark and after some trouble getting my keyboard to load its drivers and be usable (which stopped being usable for no known reason!) Mouse still worked the whole time. I began trouble shooting the keyboard issue and restarting several times...