Like most software developers, Adobe maintains a list of system requirements for Photoshop and Lightroom that can be used to help ensure the hardware in your computer system will work with their software. However, most "system requirements" lists tend to cover only the very basics of what hardware is needed to run the software, not what hardware will actually give the best performance. The processor (or CPU) is one of the most important pieces of a Photoshop / Lightroom workstation. While GPU acceleration is gaining traction, right now your choice of CPU is usually going to make a much larger impact on overall system performance. However, be aware a CPU that is theoretically more powerful is not always better since there is a limit to the number of cores that Photoshop can effectively take advantage of. In many cases, spending more money can actually result in worse performance so it is more important to get the right CPU over a more expensive one.