Which is good gtx 970 for gaming asus strix or zotac gtx 970 amp extreme or omega edition..i'm looking for buying amp extreme because it has got higher clock speed than any other gtx970 is this better choice or i w'ld go with asus. And best mobo to sli or oc the gpu i'm thinking about asus z97 A or msi z97 pc mate or msi z97 guard pro or asrock z97 extreme 3.... please suggest both mobo and gpu?