Oh, it's an Aerocool P7-C1. Looks fine for airflow.
I'd say it's the combination of the high room ambient temperature and the Duke cooler that are at work here.
The Duke cooler may be tackling a bit above it's weight class with that 330w power limit. Maybe it should've been limited to 300w like the Founder's Edition.
The card's backplate might be trapping heat too. Some of the older cards had backplates, but they were just for show. They had no thermal pads between them, so they didn't actually do anything besides make temperatures worse.
My Gigabyte Gaming OC(300w limit) didn't see over 65C when in use, but I was running the fans at 100%(I couldn't hear 'em) and the room ambient wasn't getting quite as high(closer to 30C) on hot days; I have a thermometer hanging in my room just for this.