Hello John,
XPS 8300 was shipped with 4 types of processors from Dell. Following are the list of processors shipped with the system
| Intel® Core™i7-2600,3.4 Ghz, 4C, Sandy Bridge |
| Intel® Core™ i5-2500,3.3 Ghz, 4C, Sandy Bridge |
| Intel® Core™ i5-2400,3.1 Ghz, 4C, Sandy Bridge |
| Intel® Core™ i5-2300,2.8 Ghz, 4C, Sandy Bridge |
Hence I would like to say that you already have the most upgraded processor installed in the computer.
Please write back if you have any further queries.