Yes, that is enough computer for routine tasks.
Try using Chrome as a browser. It's less of a memory hog. Definitely NOT Internet Explorer.
Install AdBlockPlus as an add-on to Chrome. That will help a lot.
And it's possible that your download speed is the culprit. Quite often you don't get the max speed you are paying for... if you read closely, your service provider says that you can have speeds UP TO whatever the cap is.
You can use the
SPEEDTESTsite to run a upload/download test. Close all your other browser tabs while doing the test.