Jerky mouse, poor responses after installing OS 10.5.7

Question

I installed OS 10.5.7 on my 20" iMac dual core Intel (3Gb RAM) about three weeks ago. Since then, I've noticed that the computer does many things poorly: Jerky mouse behavior, especially in Photoshop CS3 (but to a lesser extent in other programs), very slow to display the I/O directories when downloading an image from a reputable Web page (Stock.Xchng, MorgueFile, others), slow to open Applications Manager and other apps.
The worst offender is the Photoshop Jerky Mouse, which makes it almost impossible to do anything in PS. I have a hardwired MightyMouse, and it's brand new as of last week, but the same thing happened with the old mouse. This behavior seems to be the very worst after I've been downloading files from the Internet (almost always with Safari, but once in a while with Firefox). Sometimes, I purge the browser cache, and even dump the cookies, trying to figure out what might be lurking in the browser that affects PS.
Also, I have a second monitor, an Environ 19", which doesn't seem to produce any of it's own problems.
I have run the Disk Utilities a lot and turned off the iMac for long stretches (hours, overnight, and also 10 minutes here and there). Things seem to go fine when I start, but if I have any internet work, especially that involves downloading, I start to get the slow screen draws and the almost inevitable Photoshop Jerky Mouse behavior. (I've also tossed the PS Prefs.)
So: Is 10.5.7 dodgy? Is it a poor match for the Adobe Creative Suite 3 apps and for IDCS4 (a separate purchase from the full CS3 group)?
Thank you.

Answer 1

I too am having similar problems. It occurs in the finder, in Illustrator, Photoshop, Safari, Mail, everywhere. Sometimes the mouse simply will not click, even after repeated tries. Trying to post this message I had to click several times on the link before it worked. Usually if I hold it down for several seconds it will register a click. It is particularly aggravating to click and drag on the desktop to select and move files only to have the selection be completely different than intended. This same issue in Illustrator is infuriating.
Yes, I have tried several different USB mice.
Yes, I have checked batteries (in the mice that need them).
Yes, I have updated to the latest software.
I do have a Wacom Intuos 2 Tablet and have had different issues with it. I have tried 6.1.1-2, 6.1.0-7 and 6.08-2. It doesn't matter which one I load, or if I remove them completely and reboot, the problems with my primary mouse remain. And, on top of that, the mouse for the Intuos 2 will just simply drop my left click after a random amount of time. In Illustrator I was trying to align a point to another and after getting it close it would simply drop the point. I tested this by looking at the light on the tablet, it turns green when clicked and orange when not. It was always green, not even a flicker of orange. I also tested this in the finder by resizing the bottom right of a window. While staring at the light on the tablet to be sure it was staying solid green, the finder just drops the click and stops resizing the window.
I remember back in the earlier Mac days and even Windows (what little experience I have with that) clicking a dozen or more times while the computer was too busy to process the request that the clicks all registered perfectly in space and were held in a cue until the processor could catch up. My point being that the clicks were precisely where you intended even though they had been cached and buffered. It seems that there is no longer any buffer cue for clicks. Precision has suffered.
I was experiencing similar effects under 10.5.7 but to a lesser degree. I just assumed that my mouse was going bad. But after upgrading to 10.5.8 and testing with several mice, it is clear that there is something wrong under the hood.