I have a 24-inch Mid 2007 iMac. Should I upgrade to Yosemite?

Question

I have a 24-inch Mid 2007 iMac. Should I upgrade to Yosemite?  I was advised by genius bar that it would slow down my iMac.

Answer 1

According to sources such as http://mactracker.ca download database specs for
the iMac (24-inch Mid 2007) your computer can use more RAM than it has now.
Maximum Memory:    6.0 GB (Actual) 4.0 GB (Apple)
Memory Slots:    2 - 200-pin PC2-5300 (667MHz) DDR2 SO-DIMM
•iMac: How to remove or install memory
And so it should work better even if you stay with Mountain Lion OS X 10.8.5.
The hardware upgrade will help the Mac OS + applications, in basic functions.
[This computer is already considered 'vintage' by Apple...]
Depending on the amount of use the computer has seen so far, it may also be
a candidate for a replacement hard disk drive; perhaps a larger capacity, too.
If you consider an upgrade, also consider a complete backup and a bootable
clone of the current (if updated to 10.8.5 with its applications updated) OS X
on an externally enclosed hard disk drive with its own power supply. You can
see a few of these that do not run on Mac port power, & standalone, at OWC.
{The company known as OWC is macsales.com, a fair example of mac-centric
supplier of quality products for Mac community, awhile. Or so people tell me.}
Clone utilities such as superduper, carboncopy cloner, or disk utility can work.
Test a cloned OS X copy for boot-ability and other function before moving on.
Could be you'd be better off with this computer on Mt Lion than a later OS X.
And a newer later computer should also have hardware specs and some up-
ward expandability for use with the expected new & future changes to OS X.
Hopefully you can get some fair use and more years from your iMac 24".
And that means hope for the best, and plan for the worst. Backup, backup...
Good luck & happy computing!