I see where you are coming from, Titans are pretty good at maintaining their temps over a prolonged period, probably because they are not clocked that high in the first place. But GTX 770s are clocked very high out of the box and thinking about it I can see the temps creeping up over a prolonged period.
It would be interest if someone like whyscotty who owns a GTX 770 could test this.
Agreed, testing in Crysis 3 would be ideal IMHO.