It's a fact that a bow quiver can take vibration out of a bow. It can also stabilize a light weight bow to make it shoot a tighter group.
There is another thread on here, where I said this before, but on Tuesday night some of the guys and I were shooting in the shop for score. I took a bow off the wall and shot it reasonably well. Then I put one of our EFA Navajo I Jumbo I bow quivers on the bow. The first 4 arrows were touching each other shooting at a distance of about 14 yards. I was surprised that this bow, a Pinnacle II riser with Black Max limbs, would benefit from having a quiver on it, since it has a little more mass in the riser than most of the bows I shoot.