I just bought the Gigabyte GTX 970 G1 Gaming and this card is CRAZY. 1540mhz boost core clock and just shy of 4000mhz on the boost mem clock. No overvolting needed. The card is super quiet and even at 100 percent fans I can barely hear it! Max at 80C running furmark but barely hits 65C during gaming. Literally the best graphics card ever made in my opinion (aside from the G1 980 I guess). AMD step your game up!
Edit: Just ran the valley benchmark. Never went over 60C and the card boosted to 1679mhz on the core!! WAAAAAAAAT