the gigabyte windforce model is considerably longer than the evga acx model. i believe the evga 970/980s are about 10.5" long while the gigabyte is over 12". i personally would always want evga anyways unless there is an msi, gigabyte or asus model that is considerably cheaper.
I'd get the SC ACX, excellent cooling, not saying Windforce is not powerful, but ACX has the best blend of temps and noise IMO, besides being great OCers.
the gigabyte windforce model is considerably longer than the evga acx model. i believe the evga 970/980s are about 10.5" long while the gigabyte is over 12". i personally would always want evga anyways unless there is an msi, gigabyte or asus model that is considerably cheaper.