Pretty much all in the wheels. Shallow rims, lots of spokes. Little things. Still love my Deda Newton gear too.
By the end of the year, with a crankset change and a swap to different wheels, I should have it sub 6.8.
Superb bike to ride. Absolutely wonderful. It's apparently a bit iffy in the larger sizes but they definitely got the 51 spot on. EC90 SLX is a little bit less stiff than what I'm accustomed to. Otherwise, it's simply wonderful. Thanks go to Erik at Crank N' Cycles.