My first question, why did you go to a PCI USB Hub in the first place and did you leave it behind (remove it), like your message suggests?
What is the new hub you bought plugged into, and what is the hub itself rated as? USB 2.0?
Devices have to match USB port speed also to run at that speed.
I too have old stuff with 1.1 ports, including G11 keyboard; for running a keyboard, microphone, or mouse, 1.x is just fine, but for external storage, yes you want 2.0 or even firewire.
I dug a little deeper, and web cams will need a higher speed USB, definitely.
Did you just recently add more USB devices + the hub?
In that case you are using up bandwidth (taking it away from camera) and if it's too much then yes you will start to take a performance hit, and if you are using 1.1 USB instead of 2.0 now, you are definitely taking a step backwards and have to get back to 2.0 or you web cam is doomed to stay a laggy beast.