I think your perception is off. Time it out sometime. Load the same pages at the same time with cache and cookies and history cleared on both devices. Been there, and done that and the 9810 running 7.1 is mere milliseconds faster.
I've noticed that my BlackBerry has become quite slow all-around since updating to 7.1; don't know if it's just with my phone or not but everything seems to be running slower than before...