I bought a gtx 970 a couple weeks ago and it was great. It buzzed like crazy, but hit boost clock of 1278. Returned that card and got one that doesn't buzz but only boosts to 1240. Any reason why I've lost 38mhz with this new card? Not a huge deal as I can oc it up to 1278 or beyond, but I'm a PC noob and just wanted an explanation. Thanks.