Slow slow slow...even with low CPU and memory usage.

You may just need a little maintenance:

Kappy's Personal Suggestions for OS X Maintenance

For disk repairs use Disk Utility. For situations DU cannot handle the best third-party utilities are: Disk Warrior; DW only fixes problems with the disk directory, but most disk problems are caused by directory corruption; Disk Warrior 4.x is now Intel Mac compatible. TechTool Pro provides additional repair options including file repair and recovery, system diagnostics, and disk defragmentation. TechTool Pro 4.5.1 or higher are Intel Mac compatible; Drive Genius is similar to TechTool Pro in terms of the various repair services provided. Versions 1.5.1 or later are Intel Mac compatible.

OS X performs certain maintenance functions that are scheduled to occur on a daily, weekly, or monthly period. The maintenance scripts run in the early AM only if the computer is turned on 24/7 (no sleep.) If this isn't the case, then an excellent solution is to download and install a shareware utility such as Macaroni, JAW PseudoAnacron, or Anacron that will automate the maintenance activity regardless of whether the computer is turned off or asleep. Dependence upon third-party utilities to run the periodic maintenance scripts had been significantly reduced in Tiger and Leopard. These utilities have limited or no functionality with Snow Leopard and should not be installed.

OS X automatically defrags files less than 20 MBs in size, so unless you have a disk full of very large files there's little need for defragmenting the hard drive. As for virus protection there are few if any such animals affecting OS X. You can protect the computer easily using the freeware Open Source virus protection software ClamXAV. Personally I would avoid most commercial anti-virus software because of their potential for causing problems.

I would also recommend downloading the shareware utility TinkerTool System that you can use for periodic maintenance such as removing old logfiles and archives, clearing caches, etc. Other utilities are also available such as Onyx, Leopard or Snow Leopard Cache Cleaner, CockTail, and Xupport, for example.

For emergency repairs install the freeware utility Applejack (not compatible with Snow Leopard.) If you cannot start up in OS X, you may be able to start in single-user mode from which you can run Applejack to do a whole set of repair and maintenance routines from the commandline. Note that AppleJack 1.5 is required for Leopard. AppleJack is not compatible with Snow Leopard.

When you install any new system software or updates be sure to repair the hard drive and permissions beforehand. I also recommend booting into safe mode before doing system software updates.

Get an external Firewire drive at least equal in size to the internal hard drive and make (and maintain) a bootable clone/backup. You can make a bootable clone using the Restore option of Disk Utility. You can also make and maintain clones with good backup software. My personal recommendations are (order is not significant):

1. Retrospect Desktop (Commercial - not yet universal binary)
2. Synchronize! Pro X (Commercial)
3. Synk (Backup, Standard, or Pro)
4. Deja Vu (Shareware)
5. Carbon Copy Cloner (Donationware)
6. SuperDuper! (Commercial)
7. Intego Personal Backup (Commercial)
8. Data Backup (Commercial)
9. SilverKeeper 2.0 (Freeware)
10. MimMac (Commercial)
11. Tri-Backup (Commercial)

Visit The XLab FAQs and read the FAQs on maintenance, optimization, virus protection, and backup and restore.

Additional suggestions will be found in Mac Maintenance Quick Assist.

Referenced software can be found at www.versiontracker.com and www.macupdate.com.

What applications are you running? How many are you running at one time? How much memory do you have? How long does it take (hours) before you notice a slow down? How old is your MacBook Pro? Have you thought about doing a clean install of OS X? More info is needed to help you.

I've the same problem with my mbp...
I did the Hardware test...
I formatted and even added 8 gig of RAM... but nothing do it

One thing to consider, not just that you have 30% or so free space, but that it is highly fragmented or not; and how often or when did you last do a full ERASE and RESTORE? Say using SuperDuper or similar program, which optimizes the construction and order of folder/directories and consolidates free space into one.

I formatted and reinstalled SL, meaning that I have no third party software installed now... and got over 300 GB of free Disk Space
(also I didn't choose the fast format... so my disk has been defragmented)

Have you checked Activity Monitor to see how many PowerPC processes are running? Those "small" dashboard widgets are NOT small. Running several of them can eat up all your memory. Never heard of ThermoInDock. If you are running any PowerPC processes, kill them and make sure they don't run at startup. They can bring your Intel Mac to a crawl.

I answered your clean install question in your other posting. The answer is no, the installer doesn't know what you think is junk.

I googled ThermoInDock. Ditch that software. 1) It is BETA software (who knows how many memory leaks it has), 2) It eats up processes every 60 seconds to update, 3) Why do you need to know the CPU temp? Do you think your Mac will explode?

I am having the same issues. Had gotten better, I thought, before Safari 4.0.5 and the new MS Office 12.2.4 update, but now bad as ever. I have a Mac Mini 2.26 GHz, 8GB 1067 MHz DDR3 memory, 500 GB HD internal (156 GB available). Computer runs fine at start-up, then slows down over time. Most noticeable with MS Word and with Address Book. Machine slows to a crawl on every character I type looking up an address.

I will list the applications that run all the time from Activity Monitor, but the biggest potential offenders I see are MDS (root level, 0.0% CPU, 5 threads, 1.56 GB virtual memory) and kernel_task (root level, 1.7% CPU, 67 threads). Nothing else seems to be using excessive virtual memory, regular memory, CPU or threads.

Power PC applications -
DMRMapperApplication

Intel Applications
Garmin ANT Agent
Acrobat
Microsoft Word
Indigo 4
iTunes
Microsoft Excel
Little Snitch Network Monitor
Microsoft Database Daemon
SMCFanControl

Intel 64 Applications:
Virusbarrier X6
ARD Agent
iCal
Mail
Safari
Python
TBMobili

Just to add, inspection of the console log revealed the kernel log filled with the following:

Mar 16 07:32:36 PerryMacintosh kernel[0]: USBF: 41596.913 AppleUSBEHCI[0xd052000]::Found a transaction which hasn't moved in 5 seconds on bus 0x26, timing out! (Addr: 0, EP: 0)


Any ideas?

Hello
i think you should play with spotlight available in top right of finder

go into the system preferences

in the Personal section click on Spotlight

click on Privacy icon then click on + sign at the left bottom

and add you Local Disk then

use Utilities --> Activity Monitor to see the watch the performance

it will stop indexing your local drive for search items quickly

whenever you need to find quickly you can turn it on again

hope it will work
thanks and regards

I've seen the same behaviour for some time now on my MBP 15", 1.5 years old. My wife's MBP (13") bought about a year ago doesn't display this behaviour at all.

In addition to the symptoms you mention (low cpu, plenty of RAM) I also suffer from the excessive heat and the fan going all the time which is driving me crazy.

I've been looking for solutions for a long time with no luck.

It feels like there are things running on my computer that the Activity Monitor and top don't show.