I posted a thread in the Mac Tech Support tribe about my *hideous* iMac speed, and someone replied, "my PPC slowed way down after I used Time Machine." So supposing the problem *is* Time Machine... I don't even have the external hard drive attached to the iMac at the moment. Is there any way to disable whatever processing Time Machine is doing in the background when I'm not actually trying to use it? I may only want/need to hook up the hard drive and do a backup a couple of times a month. I don't want Time Machine doing all its overhead crap in the meantime.

Here's the original post. Any ideas, anyone?

mactech.tribe.net/thread/0d...a7bec5eccc

I have a 24" iMac. I bought it maybe a year and a half ago. When I bought it, the first thing I did was install the maximum amount of RAM it would take (at least that's my understanding). But Jesus Christ this thing is slow!! If I click on the menu bar for Finder or whatever program I'm running, it can take a good five seconds before the drop-down menu will pop up. Then I can slide over maybe five or six menu items that pop up instantly, then when I hover over the next one, it will take another five seconds before the drop-down menu will display. When I'm scrolling through something, I can get through several lines or maybe a screen, and then it will freeze for maybe five seconds before it resumes scrolling. The same thing when I'm just typing text into a window (like this one). A couple/few times a minute, the typing will just freeze for a few seconds, then a bunch of letters will appear all at once. And God help me if I'm actually trying to click on web links. Of course, nearly every time any of these things happen, I get the rotating rainbow circle telling me that it's *trying* to do something. It just can't do it fast enough. It's WAY slower than any of my crappy old Windows laptops. It feels like it's always grinding along, never able to keep up with even the simplest tasks. Is there anything I can do about this? Do I need to defrag my hard drive or something? What the hell is going on???

Here's my hardware info:

Model Name: iMac
Model Identifier: iMac7,1
Processor Name: Intel Core 2 Duo
Processor Speed: 2.4 GHz
Number Of Processors: 1
Total Number Of Cores: 2
L2 Cache: 4 MB
Memory: 4 GB
Bus Speed: 800 MHz
Boot ROM Version: IM71.007A.B03
SMC Version: 1.21f4

Any thoughts, anyone?