Slow speeds between devices
My Macbook Pro (late 2013) and iMac (mid 2011) are getting wildly different download speeds while in the same room using an Airport Extreme. They can be similar speeds, at least 1/3 of the day, but they vary the rest. I do use my airport express on the 1st floor as an extender, but the differences are not just when on different floors.
I have changed channels which sometimes helps, but sometimes does not. I have Xfinity, but I have confirmed speeds from that by hardwiring to the desktop to test.
Why the variability for my devices? The desktop is older than the laptop. The airport extreme is 3-4 years old. What can I do to improve my speeds?
MacBook Pro