Acrobit

So For these motherboards you will need to get a BIOS update which you can download from the manufactures website of the product.  Take the file and upload it on to a usb flash drive. Plug the usb flash drive in to a USB port on the I/o of the motherboard  which will be specified on your motherboard manual which one to put it in)  and connect a PSU to the motherboard to give it power and press a little button next to the USB port and wait until it stops blinking ( do not take the flash drive out or click the button again until it stops blinking and your PSU fan stops spinning or "problems")than remove the usb flash drive and you should be good to drop your new cpu right in. If you have a cpu which is compatible with your motherboard already than you can put that in and just Q-Flash it and when you are done just swap the new cpu out with the old one.

Idiotic amd vs nvidia debating aside.. 
 
I have used both the 970 and 960, in a lot of situations a 960 is sufficient, but I also ran into quite a few scenarios where the 970 could not max out(by max out I mean set every single available option to the highest possible setting, not some watered down version that other folks must be talking about when they say maxes out every game out there) and achieve solid playable frame rates.
 
Of the 2, if you're looking for something to last a while, the 970 is obviously the better choice

Then wait for Polaris and Pascal then.