Hi Cathleen,
Best thing you could do is add more RAM, depends which 2.3 though...
At the Apple Icon at top left>About this Mac.
Then click on More Info>Hardware and report this upto *but not including the Serial#*...
Hardware Overview:
Machine Name: Power Mac G5 Quad
Machine Model: PowerMac11,2
CPU Type: PowerPC G5 (1.1)
Number Of CPUs: 4
CPU Speed: 2.5 GHz
L2 Cache (per CPU): 1 MB
Memory: 10 GB
Bus Speed: 1.25 GHz
Boot ROM Version: 5.2.7f1
As far as figuring out other slownesses...
See if the Disk is issuing any S.M.A.R.T errors in Disk Utility...
http://support.apple.com/kb/PH7029
Open Activity Monitor in Applications>Utilities, select All Processes & sort on CPU%, any indications there?
How much RAM & free space do you have also, click on the Memory Tab.
Open Console in Utilities & see if there are any clues or repeating messages when this happens.
In the Memory tab, are there a lot of Pageouts?