Bulbs do age over time as the gas mixture leaks out a bit. Perhaps it's time for a new set. How long did you have them in?As the nights get longer and darker, I'm becoming less and less impressed with my 9011's and am going to swap back to my Silverstars this weekend for some perspective, at least in the low beams anyways.
High beam performance is still beyond any expectation so I'm mostly looking to increase my low beam coverage. The 9011's may throw light further down the road but I find myself wanting more light in the first couple hundred feet like my Wife's Honda.
I still have my OEM bulbs too so I may do a back to back to back comparison on the garage door and street and grab pics of each. A step I failed to do prior to any of my previous upgrades.
It's a simple game of lumens and ratings.
The dimmest H9 brand new will produce significantly more lumens than the BRIGHTEST available H11.
The spec is
70w maximum, 1760-2240lm for H9
versus 59w maximum, 1100-1400lm for H11
So your silverstars are going to be in the upper end of that range (1300-1400 lumens). The stock long life h11 bulbs are on the bottom end ~1100 lumens. Where as, the worst performing H9 is still out performing your high end silverstar bulb.