That's a big frame, I go a size smaller than the charts on a 26er ... I'm 6ft and I'd be on a much smaller frame.
But to your question: look at the inside of the crank arms, the length will be stamped in the crank, probably 175. A smaller guys MTB would probably be 170mm, that's a difference of only 1/5th an inch. Normally if the crank length is wrong you feel it as lack of power at the small end, difficulty spinning at the high end. I suppose it's possible you have custom 180mm crank on that bke, but I doubt it. But the wrong crank length is not a dramatic problem unless you are frequent rider and wired to a certain length.
I suspect you have a general fit problem, like you are way too far forward.
Bianchi Celeste Brava
Trek 7000zx, 8000sl
Miyata: 1200, 312, Alumicross, (Uv.) Gran Turismo
Specialized Roubaix Comp (happily gifted away)