Chris - thanks! Checked the speeds when I got home and the download speed is where it should be. The upload speed had decreased and seems to be varying (between 22 and 40 mbps).
However, I mainly upgraded for the purpose of smooth streaming of movies (via Netflix) using my Blu-Ray player. I was able to watch half of one movie last night with no issues. The next program I tried to watch, the same old problems started to occur - frozen screen, constant (and often unsuccessful) reloading of the program, audio but not video. I checked the speed at that time and it was hovering around 50mbps (and that was testing wirelessly as it's how my Blu-Ray player operates). Any other advice? I've read other posts where people have said it's the quality of the modem (I rent from Cox) and that it is worth the investment to purchase something a little bit better than the 'standard issue' equipment. I'm certainly willing to do that but wondered if there is anything else to try first.