slow performance diagnosis, slow performance diagnosis

Hello, see how many of these you can answer...

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 & Disk Usage Tabs.

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?

i cant identify any of the issues mentioned by You, but the performance is getting particularly slow when i process audio video files. Can You advice any cleaning diognostic APP?

See:

Mac Maintenance Quick Assist,
Mac OS X speed FAQ,
Speeding up Macs,
How to Speed up Macs,
Macintosh OS X Routine Maintenance,
Mac troubleshooting: What to do when your computer is too slow,
Essential Mac Maintenance: Get set up,
Essential Mac Maintenance: Rev up your routines,
Maintaining OS X,
Five Mac maintenance myths and
Myths of required versus not required maintenance for Mac OS X for information.

It would help us to help you if we could have some more technical info about your iMac.

If you wish, Please download, install and run Etrecheck.

Etrecheck was developed as a simple Mac diagnostic reporting tool by a regular Apple Support forum user and technical support contributor named Etresoft.

Etrecheck is a small, unobstrusive app that compiles a static snapshot of your entire Mac hardware system and installed software.

This is a free app that has been honestly created to provide help in diagnosing Mac issues.

It is not malware and can be safely downloaded and installed onto your Mac.

http://www.etresoft.com/etrecheck

Copy/paste and post its report here in another reply thread so that we have a complete profile of your Mac's hardware and installed software so we can all help with your Mac performance issues.

Thank You.