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T'hain Esh Kelch

macrumors 604
Original poster
Aug 5, 2001
6,638
7,696
Denmark
I have a 2011 iMac, quad i7 with 8Gb RAM and the stock HDD. I have trouble with my harddrive being excessively slow, and I am not sure if there's something wrong with it, or if it is the system. I have checked Apples call back for certain 2011 iMac HDDs, and mine is not one of them, based on the serial number.

When my iMac has been asleep, and I wake it up. The machine is *extremely* slow whenever it needs harddrive access (Open/saving files, open/closing programs, accessing Spotlight, etc.), and this can go on for up to 30 minutes (!), and usually takes at least 10 minutes. Even opening a tab in Safari can take ~5 seconds, and entering a website adress and clicking enter, can lead to a ~5 second wait until it finally registers and starts loading the site. Starting a new application can take up to 5 minutes. Spotlight is practically unuseable as nothing loads.

While it is going on, I can clearly hear the HDD working (No clicking, just the usual noisy I-am-working HDD sound), so I am certain that the drive is the cause. When it is done doing whatever it needs to do, the noise stops, and my computer becomes 'fast' again, ie. things open in a couple of bounces, Spotlight is instantaneous, etc. The situation is the same, albeit takes even longer, if I do a fresh boot of the computer, as it also has to load everything from the start that was open before.

I have tried to do my own damage control and see if it Dropbox, in which I have 35Gb files and would be a likely culprit, but that does not appear to be the case. Otherwise I am pretty clueless as to what can be the cause.

I usually have 100+ Gb space available on the HDD, and around 2Gb free RAM (Mavericks). Also, programs that are loaded into RAM, are usually quite responsive (Apart from when they access the HDD; as described with Safari and Spotlight above).

Are there any programs that let me check what is writing/reading from the harddrive? Activity Monitor is not very helpful in this aspect, and in most cases the read/write activity is quite low when this is going on, which is puzzling. I am starting to think that my HDD is failing. I will be upgrading to an SSD when the next generation is announced, but I would still prefer not to have a failing HDD of course. :)
 
I have a 2011 iMac, quad i7 with 8Gb RAM and the stock HDD. I have trouble with my harddrive being excessively slow, and I am not sure if there's something wrong with it, or if it is the system. I have checked Apples call back for certain 2011 iMac HDDs, and mine is not one of them, based on the serial number.

When my iMac has been asleep, and I wake it up. The machine is *extremely* slow whenever it needs harddrive access (Open/saving files, open/closing programs, accessing Spotlight, etc.), and this can go on for up to 30 minutes (!), and usually takes at least 10 minutes. Even opening a tab in Safari can take ~5 seconds, and entering a website adress and clicking enter, can lead to a ~5 second wait until it finally registers and starts loading the site. Starting a new application can take up to 5 minutes. Spotlight is practically unuseable as nothing loads.

While it is going on, I can clearly hear the HDD working (No clicking, just the usual noisy I-am-working HDD sound), so I am certain that the drive is the cause. When it is done doing whatever it needs to do, the noise stops, and my computer becomes 'fast' again, ie. things open in a couple of bounces, Spotlight is instantaneous, etc. The situation is the same, albeit takes even longer, if I do a fresh boot of the computer, as it also has to load everything from the start that was open before.

I have tried to do my own damage control and see if it Dropbox, in which I have 35Gb files and would be a likely culprit, but that does not appear to be the case. Otherwise I am pretty clueless as to what can be the cause.

I usually have 100+ Gb space available on the HDD, and around 2Gb free RAM (Mavericks). Also, programs that are loaded into RAM, are usually quite responsive (Apart from when they access the HDD; as described with Safari and Spotlight above).

Are there any programs that let me check what is writing/reading from the harddrive? Activity Monitor is not very helpful in this aspect, and in most cases the read/write activity is quite low when this is going on, which is puzzling. I am starting to think that my HDD is failing. I will be upgrading to an SSD when the next generation is announced, but I would still prefer not to have a failing HDD of course. :)

You can try repairing permissions through Disk Utility or through the Terminal with the following command:

diskutil repairPermissions /

You can simply copy/paste the above command into a Terminal window. With some problems the Disk Utility can fail to open or fail to operate. The Terminal always gets it done.
 
You can download "Blackmagic Disk Speed Test" from the App store.

Also, check that the "Put Hard Disk To Sleep When Possible" box isn't checked in your Energy Saver System Preferences. If that box is checked, it can really slow things down every time the disk has to spin up.

You can also go to Disk Utility and Verify Disk, to see if it catches any errors.
 
I have a 2011 iMac, quad i7 with 8Gb RAM and the stock HDD. I have trouble with my harddrive being excessively slow, and I am not sure if there's something wrong with it, or if it is the system. I have checked Apples call back for certain 2011 iMac HDDs, and mine is not one of them, based on the serial number.

When my iMac has been asleep, and I wake it up. The machine is *extremely* slow whenever it needs harddrive access (Open/saving files, open/closing programs, accessing Spotlight, etc.), and this can go on for up to 30 minutes (!), and usually takes at least 10 minutes. Even opening a tab in Safari can take ~5 seconds, and entering a website adress and clicking enter, can lead to a ~5 second wait until it finally registers and starts loading the site. Starting a new application can take up to 5 minutes. Spotlight is practically unuseable as nothing loads.

While it is going on, I can clearly hear the HDD working (No clicking, just the usual noisy I-am-working HDD sound), so I am certain that the drive is the cause. When it is done doing whatever it needs to do, the noise stops, and my computer becomes 'fast' again, ie. things open in a couple of bounces, Spotlight is instantaneous, etc. The situation is the same, albeit takes even longer, if I do a fresh boot of the computer, as it also has to load everything from the start that was open before.

I have tried to do my own damage control and see if it Dropbox, in which I have 35Gb files and would be a likely culprit, but that does not appear to be the case. Otherwise I am pretty clueless as to what can be the cause.

I usually have 100+ Gb space available on the HDD, and around 2Gb free RAM (Mavericks). Also, programs that are loaded into RAM, are usually quite responsive (Apart from when they access the HDD; as described with Safari and Spotlight above).

Are there any programs that let me check what is writing/reading from the harddrive? Activity Monitor is not very helpful in this aspect, and in most cases the read/write activity is quite low when this is going on, which is puzzling. I am starting to think that my HDD is failing. I will be upgrading to an SSD when the next generation is announced, but I would still prefer not to have a failing HDD of course. :)

Check the hard-drive by downloading a program called Smart Utility (can be found here: http://cloudfront.volitans-software....utility311.zip) This will check the SMART data on your hard-drive which will very quickly diagnose if it's failing. If it comes up with a warning, hard-drive's knackered.
 
Starting a new application can take up to 5 minutes. Spotlight is practically unuseable as nothing loads.

Start Activity Monitor and see if anything in the CPU tab is hogging all the CPU cycles. Also check the memory tab and look at the bottom and see if memory pressure is in the green (this is on Mavericks). If neither of these two items shows a problem, I'm going to say you have a failing hard drive.

No way even the slowest and crappiest hard drive with be as slow as you describe when functioning properly.
 
very slow HD & solution

Typically that is a symptom of a failing HD. Its a pain to replace in the 2011 iMac. Check OWC for replacement kits & instructions. I have a 2011 21.5 iMac & its always been slow, but not like you described.
My solution was to get a Rocketstor 5212 & a Samsung SSD 940 EVO 500mg.
the Rocketstor is a thunderbolt only drive cradle with 2 bays. So I use the external SSD for the boot drive & the other bay for a large HD. You can even raid the 2 drives. I got a significant increase in speed:
Black Magic
Rocketstor & SSD ~560 mbs
VoyagerQ & SSD USB3 252
VoyagerQ & SSD FW800 84

Feel like a new machine :))
 
Thank you guys.

Check the hard-drive by downloading a program called Smart Utility (can be found here: http://cloudfront.volitans-software....utility311.zip) This will check the SMART data on your hard-drive which will very quickly diagnose if it's failing. If it comes up with a warning, hard-drive's knackered.
Smart Utility informed me that everything was fine.

There's your answer.

Download Blackmagic Disk Speed Test off the App Store. If it's below 100 MB/s, there's your problem.
This is 25 minutes after a fresh boot, with the harddrive silent.

If I do while it is chucking away, I reach 5-40 MB/s on both read and write.
Disktest.jpg


Start Activity Monitor and see if anything in the CPU tab is hogging all the CPU cycles. Also check the memory tab and look at the bottom and see if memory pressure is in the green (this is on Mavericks). If neither of these two items shows a problem, I'm going to say you have a failing hard drive.
98% CPU free, around 5 minutes after a fresh boot. Hardrive keeps chunking away though. Screenshots here are taken 25 minutes after a fresh boot, when the harddrive finally stopped doing whatever it was doing (Notice the flat read-line). I guess the 7.2 GB stuff that has been read must be the problem? What could potentially be that large? I have Safari, Mail, Dropbox, iTunes, iMessages open, along with the apps used for screenshots.
io.jpg



Typically that is a symptom of a failing HD. Its a pain to replace in the 2011 iMac. Check OWC for replacement kits & instructions.
I already bought a OWC kit. I am just waiting for Samsung 850, or whatever they'll release soon (I hope!).
 
98% CPU free, around 5 minutes after a fresh boot. Hardrive keeps chunking away though. Screenshots here are taken 25 minutes after a fresh boot, when the harddrive finally stopped doing whatever it was doing (Notice the flat read-line). I guess the 7.2 GB stuff that has been read must be the problem? What could potentially be that large? I have Safari, Mail, Dropbox, iTunes, iMessages open, along with the apps used for screenshots.

You have plenty of memory, so that's not an issue. Try to look at CPU while the hard drive is thrashing around and look in the CPU tab to see if any one process is running high CPU usage.

Also, try a safe mode boot and see if it does it then. A safe mode boot runs a stripped down system and by passes and login/startup items and can be helpful troubleshooting if this is a misbehaving app.
 
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