Most PCs today have processors that use?

Intel and AMD are the biggest companies, though Intel is probably the most popular.  The current lineup of Core processors includes the latest Intel Core i7, <a href="www.intel.com/en_uk/Consumer/Products/Processors/corei5.htm">Intel Core i5</a> and Intel Core i3, and the older Intel Core 2 Solo, Intel Core 2 Duo, Intel Core 2 Quad and Intel Core 2 Extreme lines.