Lion’s system informationRight in your computer’s Apple menu , the first item in fact, is the “About This Mac” utility. Clicking on it will bring up a small window that prominently says which version of Mac OS X you’re running, which processor your system has, how much RAM, and the name of the startup disk (the drive the computer boots from). There are two clickable buttons in this window: one takes you to Software Update, and the other, which we’ll be using, is labelled “More Info…” and takes you to the System Information app.
The System Information app provides you with the type of Mac you’re using (iMac, MacBook Pro, etc.) and also the specific size and original release timeframe of the computer. In the screenshot below, you can see that I’m using a 27-inch iMac from mid-2011 here.
Listed along the top of the System Information window are different tabs where you can find out more. “Displays” shows you the number and type of screens currently being used by your Mac, including the built-in display and any external monitors you have connected.
“Memory” tells you how much RAM you have installed, and lets you know if you have any free slots available for more. You can also access Memory Upgrade Instructions from this tab for your specific model of Mac, if the memory is user-upgradeable.
Back under the Overview tab, you can click “System Report…” to get a more detailed look at your system and the hardware installed, but for most users, what you need to find should be listed in one of the tabs mentioned above.
Mactracker and EveryMac.comIf you’re still curious about your Mac or any other Mac out there, then there are a couple useful resources you can check out. Mactracker is an app on the Mac App Store that’s available as a free download. You can use it to browse or search for any Mac model ever built, as well as Apple-made peripherals, iOS devices, servers and even discontinued product like the Newton. It’s like a virtual Apple museum that’s both searchable and customizable.
EveryMac.com offers similar information, but in a website instead of in an app. It’s a little bit harder to navigate, but once you find what you’re looking for, it provides much more detailed information, including lengthy contextual descriptions of the Macs themselves, as well as Geekbench performance comparisons, and links to helpful articles about specific components and their uses.