Just so you know the Intel® Core™ I5 650 is a dual core processor that has hyper-threading. If you are looking for a 1st generation Intel Core processor that is a quad take a look at the Intel Core I5 750. Or if you are looking for a 2nd generation Intel Core processor that is a quad you can check out the Intel Core I5 2500. You can see some information on all of these processors at http://ark.intel.com/Compare.aspx?ids=52209,42915,43546,.
The Intel® Core™ I7-2620M is a very nice processor in the mobile environment. For gaming this dual core processor with hyper-threading would be a very good processor except for applications that are heavily multi-threaded will take advantage of 4 threads or more. With that type of software a full quad core laptop processor might have an advantage if it was running at close to the same speed.