have you been running those 2 inchers at 80-90 without a load or with one, and if yes, how much weight?
I have used 1.5 marathons regular at about 65psi with about 25lbs on the rear rack only, and that pressure works well. I do only weigh 140, but it seems to me that at 80-90 you are putting a lot more stress into your wheels and spokes.
Ive used 26x2 Supremes a bit and wouldnt run them at 90 unless I was loaded a lot, and frankly, even then in my experience that is simply too much.

I am convinced that higher pressures like that on a 2 in tire is working against you, less comfort and harder on the wheels. Allow the tire to do some more suspension effect and it wont be slower--within limits of course on pavement, but if you have a good floor pump, try various pressures for a given bike weight and ride the same route to really feel the difference. On rough paved roads, bringing them down from 80 or 90 to 60 or 70 will be a diffference you will really feel in being less beat up, with no real loss of speed.

I ride a route of about 10-12km as a commute and as I take the same roads, with all the potholes and rough stuff here and there, its a great way to try diff tires and diff pressures and really see how they feel, both in ride quality and effort required, and also to roughly compare ride times. Oh, and with diff weights too, so a bunch of factors that I can try out as I am commuting anyway, so fun to try stuff and actually feel the difference.