AMD and Pentium are known to be processors that you may have when you are using computers. When it comes to overall performance, Pentium is known to be better. You can expect that you will be able to do your tasks faster. There are some reports, though, that state that AMD processors are now faster than before.
Some people have a general preference, and you can consider your preference, too when you are purchasing the right processor for you. Just remember that you need to take note of the model if you really want to make the best decision. Can you imagine if you are purchasing the oldest Pentium processor? Other newer AMD processors will probably work better because of the upgraded features.