Become a MacRumors Supporter for $25/year with no ads, private forums, and more!

My reconditioned iMac Retina 4K 21.5 inch 2017 3.6GHz i7 is slowing down markedly

Stadders

macrumors newbie
Original poster
Aug 28, 2014
11
0
West Country UK
I wonder if anyone can help
My reconditioned iMac Retina 4K 21.5 inch 2017 3.6GHz i7 with a is slowing down markedly. It has a 1Tb fusion drive and the time machine runs on a 500Gb USB drive. When it arrived it whipped along like a greyhound. Now it seems to be forever running the Timemachine and the fans are really quite noisy. I only have 6 and a bit Gb of space left on the time machine drive. I was wondering if I was to get a 2Tb SSD drive and run it from one of the Thunderbird ports with the opearting system on it and run the internal Fusion Drive as the time machine drivewhether this might solve the problem. Of course if I do this I will be back for advice on how to do it!. I so enjoyed its initial speed but it has just become sluggish. Or is there likely to be a more serious problem.
 

chscag

Contributor
Feb 17, 2008
3,931
1,411
Fort Worth, Texas
How full is your internal drive? Also, that model uses a slow rotating (5400 RPM) drive in conjunction with a small SSD combined as a Fusion drive. As you said, you can probably speed things up by booting the machine from an external SSD attached to one of your TB 3 ports and running the system from there.
 
Comment

Agilato

macrumors newbie
Jun 5, 2020
22
1
External SSD as boot drive will give you consistent 700mb/s both ways, way better than fusion.
Also i noticed that with USB-C SSD for backups system process backups way faster.

Make sure External SSD is USB 3.1 Gen 2
 
  • Like
Reactions: sracer
Comment

vertical smile

macrumors 603
Sep 23, 2014
5,321
6,184
As others mentioned, I would suggest using an SSD, either externally or internally.

The 1TB Fusion Drive on your model only includes a 32GB SSD, so it will fill up really quick. Newer MacOS versions seem to not run well on HDDs with APFS.

The easiest solution would be using an external SSD. You could then use your internal Fusion as storage, Time Machine, Bootable back up, etc.

Your HDD could be failing, but either way, I would just still with a SSD.

My reconditioned iMac Retina 4K 21.5 inch 2017 3.6GHz i7
Where did you get this iMac from?
 
Comment

Stadders

macrumors newbie
Original poster
Aug 28, 2014
11
0
West Country UK
As others mentioned, I would suggest using an SSD, either externally or internally.

The 1TB Fusion Drive on your model only includes a 32GB SSD, so it will fill up really quick. Newer MacOS versions seem to not run well on HDDs with APFS.

The easiest solution would be using an external SSD. You could then use your internal Fusion as storage, Time Machine, Bootable back up, etc.

Your HDD could be failing, but either way, I would just still with a SSD.


Where did you get this iMac from?
A UK company specialising in refurbished Macs. It has become quite noisy as well. I wonder if something is about to go down?
[automerge]1593685373[/automerge]
How full is your internal drive? Also, that model uses a slow rotating (5400 RPM) drive in conjunction with a small SSD combined as a Fusion drive. As you said, you can probably speed things up by booting the machine from an external SSD attached to one of your TB 3 ports and running the system from there.
there is 635Gb left of the 1TB
 
Comment

mj_

macrumors 65816
May 18, 2017
1,087
675
Austin, TX
Check activity monitor for any processes that might be causing high CPU load. A full or busy hard drive will not make the fan spin.
 
Comment

Stadders

macrumors newbie
Original poster
Aug 28, 2014
11
0
West Country UK
I have the CPU at between 95% and 97% Idle. The mac seems to be burbling or mumbling in the background with the fan almost continually running. Sometimes the fan is really Loud
 
Comment

Agilato

macrumors newbie
Jun 5, 2020
22
1
i7 on latest OS can run hot, always take in count that each new OS will load your computer more than previous.
If those service guys used cheap thermal paste it could dry out or iMac might have dust clogged inside.

Install Macs Fan Control and check your temps.
If temps are in range of 40s looks service that reconditioned it used non apple HDD.
And it drives your iMac crazy, if so use same program to set proper fan spin curve.

I spent last week testing it, 3.5inch HDD's still has to be original Apple Seagate.
Only with 2.5inch drives (SSD/HDD's) fan aren't fully throttling.
 
Last edited:
Comment

Stadders

macrumors newbie
Original poster
Aug 28, 2014
11
0
West Country UK
i7 on latest OS can run hot, always take in count that each new OS will load your computer more than previous.
If those service guys used cheap thermal paste it could dry out or iMac might have dust clogged inside.

Install Macs Fan Control and check your temps.
If temps are in range of 40s looks service that reconditioned it used non apple HDD.
And it drives your iMac crazy, if so use same program to set proper fan spin curve.

I spent last week testing it, 3.5inch HDD's still have to be original Apple Seagate.
Only with 2.5inch drives (SSD/HDD's) fan aren't fully throttling.
Is there a particular site where one can get this Mac Fands Control, I am just a bit worried about software from free folk. What's in it for them? Maybe I am just mercenary myself and should have more generous thoughts!
 
Comment

mbosse

macrumors 6502
Apr 29, 2015
471
116
Vienna, Austria
I wonder if anyone can help
My reconditioned iMac Retina 4K 21.5 inch 2017 3.6GHz i7 with a is slowing down markedly. It has a 1Tb fusion drive and the time machine runs on a 500Gb USB drive. When it arrived it whipped along like a greyhound. Now it seems to be forever running the Timemachine and the fans are really quite noisy. I only have 6 and a bit Gb of space left on the time machine drive. I was wondering if I was to get a 2Tb SSD drive and run it from one of the Thunderbird ports with the opearting system on it and run the internal Fusion Drive as the time machine drivewhether this might solve the problem. Of course if I do this I will be back for advice on how to do it!. I so enjoyed its initial speed but it has just become sluggish. Or is there likely to be a more serious problem.
I think part of your problem is the little space in your TimeMachine drive - with only 6GB left TimeMachine has to do lots of additional work: discarding older backup files while writing the new ones.

I'd first get a large backup disk (2 TB) and see whether this changes things - I am pretty sure it will.

Also, it would not hurt to install DriveDX (15 day free trial period) and see whether one of your internal drives has an issue.

Best,
Magnus
 
Comment
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.