Ah the thorny question, what is the best OS for my Mac. The simple answer is, it's a bit complicated. Some Macs can run any updated version of the OS up to the latest (macOS Sierra0, some macs top out at OSX 10.11 also known as El Capitan, other, older Macs are stuck at OSX 10.7 (Lion) while the positively geriatric are only able to reach OSX 10.6.8 (Snow Leopard). If you have a pre intel Mac then stop reading now, nip over to the refurbished Macs page on this site and get yourself updated. You know it makes sense.
So, how does all this pan out in practice. Well, lets start at the bottom. (ooh err missus). The very earliest Intel Macs are limited to running OSX version 10.6.8. In general they run this fine as it's a light weight OS that is pretty speedy on older hardware. The main issues come with its limitations. Ni iCloud for you, also, no internet as all current modern browsers (Safari, Chrome etc) are no longer available in 10.6.8 guise. No Flash player either, so no BBC iPlayer or YouTube. All in all if you are running one of these early Intel machines it's probably well worth the updating to a much newer and faster machine.
Macs stuck on 10.6.8 are:
- White/Black v1 MacBooks with the Intel CoreDuo processor (2006 models)
- Aluminium 15in MacBook Pro's with the CoreDuo processor (2005-6 models)
- Mac Mini with CoreDuo processor (2005-6)
- White 2006 iMacs
Next up is OSX 10.7 (Lion), also known as the Windows Vista of Mac OS. All Intel Macs will run this but unless it's the newest version you can use, you are best off upgrading. Lion tends to run slow, is buggy and the newer style user interface is unfinished and confused. Browser support is also now missing for Lion so again, limited Internet for you.
Macs stuck on 10.7.5 are:
- All white/black MacBooks with Intel Core2Duo processors (2006-2008)
- 2007 15in MacBook Pro model 2,2
- Mac Mini 2007
- Mac Pro 2006-7
- White 2007 iMacs
Things do settle down a bit after this. Any Mac built after the above is happy running any version of OSX up to 10.11.6 (El Capitan), although many older Macs will benefit from additional RAM in order to do so with usable speed. A hard drive upgrade to an SSD will also speed things along a lot. Sadly after hanging on in there through the increasingly bizarrely named Mountain Lion (10.8), Mavericks (10.9), Yosemite (10.10), El Capitan sees a cut off for other older Macs,
Macs stuck on OSX 10.11.6 are:
- Aluminium iMacs from 2007-2009
- Unibody MacBook Pro's from 2008-9
- Mac Mini 2009
- Mac Pro 2009
Broadly speaking, with RAM, each Mac model is best off running the latest version of the OS that it can. Apart from keeping things up to date this also means you get access to the current versions of applications, browsers and other stuff that keeps your Mac functional for the longest amount of time.