Patrick, I'm just hoping for a stable operating system that I don't have to worry about for a few more years. If it's a lot faster, that would be wonderful too. 😉
No doubt it will be faster for some things but do make sure it also has adequate amount of RAM installed to help things out, and that iMac can use a maximum of 6GB, and 4GB should be your installed MINIMUM!!!
And definitely the 6GB RAM if you're going to go to to the Maximum MacOS: X 10.11.x it can use.
I had read on a few sites that 6 mb ram could be used by this machine even though it calls for 4 gb max. Would it be o.k. to just take out one 2 gb stick and replace it with a 4 gb stick or do they need to be a matched pair. Would I need to install a new 2 gb and 4 gb?
BTW, I was considering just leaving the OS at 10.7.5 Lion. It works for me! Also, thanks for the link. I'm going to check them out.
Check out the info at canadaram.com regarding the memory module size to use.
6GB is the Max Ram for that iMac. Apple never bothered to update the actual info or facts.
As for updating your OS X, you may be restricted in your choice if you never downloaded any later version from the App Store. You may be able to purchase 10.8.x, or 10.11.x may be available to you via your Apple ID App Store.
"*This system can run the last version of OS X 10.8 "Mountain Lion", OS X 10.9 "Mavericks", OS X 10.10 "Yosemite" and OS X 10.11 "El Capitan" including booting in 64-bit mode. However, it does not support OpenCL nor does it support AirDrop, AirPlay Mirroring (which also requires a 2nd Gen or later Apple TV), Power Nap, or other advanced features, either. It is not capable of running macOS Sierra (10.12) or subsequent versions of the macOS at all." iMac "Core 2 Duo" 3.06 24-Inch (Early 2008) Specs (Early 2008, MB398LL/A, iMac8,1, A1225, 2211) @ EveryMac.com
For maybe similar 2008 iMac specs…
Just be aware that OS X 10.7.5 Lion is getting less and less support and almost nothing from Apple and you'll get cut off more and more as time goes on.
And I sure hope you have a current working backup.