Certain newer components are not compatible because drivers don’t exist. There are pitfalls: Installing new CPUs sometimes involves “ delidding” a processor, which means removing a shield from it to make it compatible with the 4.1 or 5.1. 'We’re helping the company close this huge stopgap between 2013 and whenever they introduce the new Mac Pro' For some things, it’s better than any Mac offered at the moment.” We’ve found a way to put two good ones in old Macs. To do what a lot of pros want, you just need a good GPU. “With CPUs, nothing drastic has happened in. “We’re using the skeleton of the machine,” Gianluca Mazzarolo, owner of the Denmark-based Big Little Frank, which makes custom Mac Pros for creative professionals, told me on the phone. The Facebook group Mac Pro Upgrade is filled with people scooping up old Mac Pros from eBay and Craigslist and modifying the hell out of them.

People are putting new CPUs, RAM, SSDs, and modern graphics cards in the cheese grater Macs that are, in many cases, superior to what you can buy from Apple today. Upgraded versions of the 4.1 and 5.1 are, in many cases, the fastest Apple computers you can buy today.

These are the last highly upgradeable and modifiable desktop computer that Apple sold before moving to the much-maligned “black trash can” design that is sold today and hasn’t changed significantly since 2013. The Mac Pro 4.1 and 5.1 are known in the community as the “cheese grater” Mac Pro towers.