Mac hangs even with low memory and CPU usage

I have a G5 2.3 Ghz, with 10.5 GB Ram, running OSX 10.5.8.

I have noticed that following a restore from Time Machine that my mac is hanging a lot and running slow. I opened my activity monitor and at the beginning it was obvious that much CPU usage was directed to indexing. However, it has been days now and it still hangs on a number of programs despite the fact that activity monitor shows little CPU or memory usage. What can cause this? It also gets really bad while backing up the system with time machine. I kind of understand that to some degree but it hangs really bad. It has hung 4 times while trying to type this message. I have run disk utility and it shows the disk and permissions are fine. I have also checked all memory and it appears to be working fine as well. It just seems like my computer is not taking advantage of the CPU or memory. The worst problems have been with things like Safari, Quicktime, Photoshop, and while downloading with uTorrent. Any ideas?

Could you solve this issue? I'm experiencing similar problems with my MacBook Pro Core i7 2GHz running OS X 10.7.2.

1) How much disk space do you have left on the start up disk ?
You should left 15% unused .
2) Start you,re Mac in the verbose mode ,and see it comes with error messages

Not sure if you have the same problem but mine turned out to be a bad hard drive. Once replaced all was back to normal.

dobby said:

1) How much disk space do you have left on the start up disk ?
You should left 15% unused .

Click to expand...

I've got about 50% unused disk space (522 GB of 1 TB are free).

dobby said:

2) Start you,re Mac in the verbose mode ,and see it comes with error messages

Click to expand...

The only errors I saw were "Dubious ownership on file (skipping) /Library/LaunchDaemons/com.hidden.daemon.plist" (see Hidden - The most advanced theft tracking software for your Mac.) and "nstat_lookup_entry failed: 2" which appeared twice.

I have the itchy feeling that it has to do with network connections. But neither is the traffic high when the system freezes/slows down (all applications show a spinning beach ball of death), nor is the CPU load anywhere to be called "high".

Sometimes even the applications respond and the Dock shows the contextual menu, but then only texts like "APP_QUIT" appear in place of "Quit".

The message nstat-lookup-entry failed : 2 well nearly every body get that message .
If only appear twice just ignore it .
To be totally sure check you're kernel log .
If it appear often it can slow down you're Mac
Do you have that tracking software on you're MAC ?
And did you use it ?
Do you use any cleaning app and the mackeeper in particular ?
If you use cleaning software uninstall it using AppTrap .

dobby said:

The message nstat-lookup-entry failed : 2 well nearly every body get that message .
If only appear twice just ignore it .
To be totally sure check you're kernel log .

Click to expand...

It doesn't appear often. Very seldom to be exact.

dobby said:

If it appear often it can slow down you're Mac
Do you have that tracking software on you're MAC ?

Click to expand...

I did, but I uninstalled it. After seeing the error message above, I removed the remaining files that the uninstall procedure at HiddenApp described.

dobby said:

And did you use it ?
Do you use any cleaning app and the mackeeper in particular ?
If you use cleaning software uninstall it using AppTrap .

Click to expand...

I don't use cleaning apps. Especially not MacKeeper.

I'm now observing this a bit more - running Activity Monitor the whole time, to backtrack what happens during a freeze. Maybe the will shed some light on this issue.

(Edit) And thanks for your in-depth support!

Boot from your Leopard install disc, go into Utilities > Disk Utility and run Repair Disk from there and see what is reported. Sounds like a failing hard drive.