Well usually the NB and VRM cooling is in the same like on my ASRock so both my northbridge and VRM's get scorching hot. Now on your evga the SB and NB are linked and the VRM's have there own. For my board my VRM's get the hottest.
I guess you'd have to have some other's give you better information. But you should definitely see what you can clock to as you haven't even tried stressing the board with any OC's yet. I'd say mount a fan on your VRM sink and you should be good.