could be sucking the lower hose closed

check for a spring in it

add one if its not in there

also check flow of rad

a/c or non-a/c ?

right pulleys with the right # of vanes on the pump?

I bump all my 5 blade fans up to 7 blades on a themo fan clutch

changing the anti freeze yearly is good but does not mean it will not have settament in the core of the rad

do you back flush it when changing the freeze?

does not sound bad right now..but it could be heading that way on the temp rizing up at speed