Apple Compatible Solid-State Drive Upgrades
Mac Compatible SATA SSD'sFor many legacy Mac's and MacBooks, a very affordable off-the-shelf 2.5" laptop-size 6Gbps SATA III SSD is the right choice. When used with a 2.5" to 3.5" drive adapter sled or case it's also the right choice for older Mac Pro towers and iMac computers which used full-size 3.5 inch drives.
Peak Read / Write SSD Performance
Mac Compatible ATA-IDE SSD'sFor older G3 and G4 Macintosh models there are a few 2.5" IDE solid-state drives that can be a drop-in replacement for Mac Mini and iBooks. With an adapter, some can be retrofitted to tuck an IDE SSD into an iMac or other full-size Macintosh 3.5" drive bay common at the time.
For G4 Era iBook MacBook Mac Minis
MacBook Compatible SSD'sFrom the original white MacBooks and early MacBook Pro's through around 2012, a standard 2.5" SATA SSD was generally an easy upgrade. As with other Mac's, modules supplanted standard drive form factors, first with custom M.2 SATA and then as of 2014, custom pinout PCIe NVME SSD modules.
The compatible MacBook Air SDD timeline is most complex since, as the 1st Macs to feature solid-state storage has transitioned from 1.8" ATA-IDE to 1.8" SATA I, then II, then III, then onto custom-pinout M.2 SATA modules, to the more recent M.2 PCIe modules.
iMac Compatible SSD'sWhite Plastic iMac's - both G5 and Intel used 3.5" SATA interface drives. Thick bodied Aluminum iMac's used full-size SATA drives as well. However with the ultra-Slim Aluminum iMac, Apple moved towards 2.5" laptop size SATA hard drives with (optionally) a custom SATA SSD module. We recommend complete iMac drive upgrade kits specific to your model with the proper tools and other things needed to complete the drive swap.
Mac mini Compatible SSD'sFor Intel CPU based Mac minis, a 2.5 inch SATA SSD is the right choice, for older G4 Mac mini's you want an IDE-ATA interface 2.5" laptop size drive for upgrading.
Mac Pro Compatible SSD'sThe Mac Pro cylinder models use a custom PCIe SSD module. There aren't many aftermarket upgrade options. OWC/MacSales is your best bet, followed by MCE which supplies larger, factory original Apple PCIe modules in larger sizes than your Mac Pro came with.
The Aluminum Mac Pro Towers offer two solid-state drive upgrade options. One is to use a readily available drive tray/adapter to convert an off the shelf SATA SSD to 3.5" drive bay. Another option is the use of a PCIe SSD card which can typicially support either 1 or 2 2.5" SATA SSD drives, or more recent ones that support M.2 SATA or even PCIe SSD modules.