Make my iMac less "crunchy"?

I have an iMac with 8g of memory and a half full HD. Ive had the iMac about 5 years now and am extremely pleased with it. In fact the only time I get a problem its undoubtedly associated with a festering Windows problem (silverlight, Office for Mac etc!).
However, I do find that the system seems to be doing a lot of crunching when I log on and if I change users over. It sounds like there is a lot of file swapping going on. I can understand that if I am changing users but not when logging on. I suspect there is a lot of rubbish on the system after 5 years so I think there is a need for some sort of "clean up". Some Mac users say there is no need to do this as the system sorts itself out but I am not sure. Once logged on there does not seem to be any problem with speed unless I start one of the Office programs then there is a lot of crunching going on!
Anybody any suggestions please?

It could be that the drive is getting ready to fail. It could be that you keep a lot of apps open and the machine has to rely a lot on "virtual RAM" (disk space) when called upon to do something more complex while a bunch of apps are open.

The one thing I can tell you that you DO NOT need is ANY mac program that advertises it will "clean up" your computer. For maintenance, we recommend the following procedures ONLY:

1. Keep plenty of HD space free (you're doing that already).
2. Make routine backups by whatever methods you like.
3. Run OnyX (free) on Automatic every few months.

That's it. If you're still having problems with "crunchiness," I'd replace the hard drive. After five years, however, you might want to start considering your next machine.

While the above is good for those not asking the question (nor having any concerns) about the speed of their machine, for those that do want their machine running as fast as it did when new and... I don't care what anyone else has to say about it...

After 5 years and with a drive that has over 40% used space, your data and free space is going to be spread out from one end of the drive to the other. Even the kexts required to boot into the OS will be spread out across the drive (causing the "crunching" because the arms are having to move all over the patters) particularly if you've installed newer versions of OS X a couple of times over the top of the old without a clean install.

4. Defragment the drive by either:

1. Using Superduper! or CarbonCopyCloner to make a bootable clone of your drive, boot to the clone - make sure it is fully functional and all your data is there - then clone back to your internal drive.
2. Grab iDefrag and defrag the drive - this option will provide a 10-15% faster boot time that the clone method.

In my testing, iDefrag has consistently delivered boot times at about 32 seconds on 5400 RPM drives and 26 seconds on 7200 RPM drives. Tested by temporarily removing the log in and booting directly to a fully functional desktop. I see about 16 seconds to the login screen on my WD Black drives.

Replacing the drive with a newer and larger drive and then installing OS X / restoring from your backup would do it also. I still recommend the WD Black for system drives and would undoubtedly be faster than the drive your iMac came with.

You have enough free space on the drive. The threshold of used/free space for me personally is 65/35 before I get to the point that "only" by freeing up more space can I improve my "user experience". That threshold can move to as much as 80/20 and even 85/15 to meet the expectations of many users. While OS X will never need to be defragged as often as your old Windows machines, when you get to the lower end of the amount of free space, even greater is the need for an occasional defrag.

Thank you Bobtomay. I have been consistently told that there is no need to defray a Mac! So I will get a copy of iDefrag and see if the files are all spread out.

oldmoondog said:

Anybody any suggestions please?

Click to expand...

Give this article a read:

Defragmenting a Mac Hard Drive: Is It Necessary? | OSXDaily

Read both the top part about defragmenting…and the lower ("so now what") part.

Much of what the article states has already been mentioned by others in the thread…but there may be a couple extra nuggets of info.

- Nick