Currently Being ModeratedDec 29, 2012 12:46 PM (in response to barbarafromedwards)
Do you have 2GB or 4GB+ of memory (click the apple on the left of the menu bar, and then about this mac)? If 2GB, that's the minimum required to run OS X 10.8 Mountain Lion, and many have found that you really need 4GB for reasonable performance. Recommend Crucial or OWC as reliable sources for memory.
Currently Being ModeratedDec 29, 2012 3:03 PM (in response to barbarafromedwards)
How much free disk space do you have? General rule is to keep 10% of your hard drive free for systems usage. Less than that can impact performance.
If you open Activity Monitor (on your hard drive in application/utilties or Launchpad under Utilities) on the system memory tab, what's it say for page ins and page outs? If page outs are 10% to 15% of page ins, then you can use more memory for what you run.
Currently Being ModeratedDec 29, 2012 4:35 PM (in response to barbarafromedwards)
I got your reply via email, however, it hasn't shown up here yet (?) You said "I have 3.74 GB outs and 2.31 GB ins - I have no idea what this means!"
When OS X runs out of physical memory to run programs, it writes sections of memory to the hard drive to make room for other programs to run. This making room is called a page out. In a memory perfect world, page outs would be zero, since there would be enough memory to run everything. However, that's rarely the case.
What your numbers mean is that, since your last boot (the numbers reset when you boot), your system has read in 2.31GB's of data to work on, however, it's paged out 3.74GB's or 162% of page in's. Where the gauge for the right amount of data is page outs being 10% to 15% of page ins, yours is at 162%, for the programs you run!
While you have 4GB of memory, your page outs suggest you need to at least 8GB for the programs you run. You could just replace one memory card to get to 6GB, however, the Intel architecture runs a bit quicker (3% to 5%) with matched memory, for example two 4GB cards.
That could explain why you've seen less than optimal performance, even with 4GB of memory.