1TB Fusion Drive 2013 27" after OS clean install - Terrible Performance

[kirkster501]

Just updated the OS with a clean install of Catalina for 27" iMac late 2013 i5. Original 1TB fusion drive and machine has been mine since brand new in Dec 2013.

Performance of the fusion drive is appalling at about 20MB/s - TBH I never tested it before the reinstall of OSX. Apps like Word and Photoshop now take forever to open. It is FAR worse now than it was before I reinstalled the clean OS.

Any thoughts please as to what is going on? The only things I have installed are Office, Adobe and Chrome.

I am not overly concerned since I am going to update the NVMe to a 2TB and remove the HDD completely.

 

[kirkster501]

Hmmmm, rebooted and it now appears a bit better - at about 80-100MB/s.

I get an initial pulse of higher speed at about 140MBs and then it slows down to about 50MB/s. Is this the fusion drive's SSD "filling up" and then slowing down I wonder? After 5 mins of this is stabilises at about 50MB/s.

 

[Juicy Box]

There was most likely indexing happening with the new OS install, this could go on for hours, even days.

Also, you Fusion Drive is going on 8 years old, so slow downs isn't unrealistic. Not, 20MBps, but sub 200MB per second isn't unexpected.


A side note, HDDs and Fusion Drives have been known to have decreased performance on APFS and especially on Catalina.

I high suggest using a SSD. Using a SSD on an old Mac will make it feel new again, and this is even more true with Catalina.

You can get a 1TB SATA SSD for less than $100, and get a cheap $10 USB enclosure or USB/SATA adapter. This will give you speeds about 350-400MBps. The biggest (only?) downside is the lack of TRIM support.

I have a couple of these:

SABRENT USB 3.0 to SSD / 2.5 Inch SATA I/II/III Hard Drive Adapter (EC-SSHD)

Product Description:Take advantage of the lightening speed of USB 3.0 to quickly transfer files up to 5 Gbps! Connect any 2.5'' Serial ATA (SATA) / SSD or SATA II Hard Drive to your computer through an available USB 3.0 port on your desktop or laptop. Reverse compatible with USB 2.0 and 1.1, this...

www.amazon.com

The price is now up to $10, they were $6 when I got them, but I still think they are worth it. I like the longer cable of that one compared to many other ones out there.


If you want something faster, or if you plan on using this for the very long term and want TRIM support, consider getting a SSD over TB.

I am currently using a TB3 NVMe SSD on my Late 2012 iMac, and get speeds up to 900MBps. I think that is probably overkill, and not worth the investment, but you can get a TB2 NVMe drive for cheaper with about 700Mbps speeds.

 

[Juicy Box]

I just thought of something.

It is a long shot, as I wouldn't know why it would be disabled, but check in your system profiler to make sure that TRIM is enabled on your Fusion Drive.

 

[kirkster501]

Thanks, yes the indexing could be the reason. That makes sense.
TRIM is supported it says.

Why is my 1TB fusion drive only showing 150Meg free when I have only installed about 80G of apps? Some stuff is downloading from Onedrive but all the same not even 10% of that volume of data.

Yes will definitely update the NVMe to a 2TB and stick a 8TB HDD in for mass storage.

 

[kirkster501]

Ok, after leaving machine for a few hours the speeds seem to be much better. Maybe indexing and stuff was going on in the background after the reinstall.

Apps do seem to be bouncing a *lot* though upon opening them, takes a minute to load Lightroom Classic for instance. I will give it a couple of days to see if the machine settles down.

 

[Juicy Box]

Apps do seem to be bouncing a *lot* though upon opening them, takes a minute to load Lightroom Classic for instance.

This could be normal behavior for a Fusion Drive, especially after a clean install, and will get better the more you use your machine.

It could improve in as little as a day or two if you use the same apps and files often.


Another thought, maybe your HDD is starting to go. Make sure you have a bootable back up incase the HDD fails.

 

[nambuccaheadsau]

When I had the same model Black Magic showed Read at 620 and Write at 270 so it may well improve.

 

[kirkster501]

...those are impress enough figures that in the real world would upgrading to a large NVMe actually make that much difference? ......

 

[Juicy Box]

...those are impress enough figures that in the real world would upgrading to a large NVMe actually make that much difference? ......

Are you referring to the speeds you posted or the ones that @nambuccaheadsau posted?

If you are referring to your speeds, noticing a difference totally depends on what you do with your computer, but I would highly recommend using a straight SSD if you can.

If you access the same apps and files everyday, and not benefit from the higher write speeds from what you do, you may not notice too much of a difference by going to a faster drive.

Also keep in mind that BMDST only tests large sequential reads and write, which is helpful for certain tasks, but not real world experience which is usually random.

Use AmorphousDiskMark to do a better test of your Fusion Drive's speed. Here is the Mac App Store link:

‎AmorphousDiskMark

‎AmorphousDiskMark measures storage read/write performance in MB/s and IOPS. • Sequential 1 MiB block read/write measurements with Queue Depth=1, 2, 4, 8, 16, 32, 64, 128, 256, 512, or 1024 • Random sequence 4 KiB block read/write measurements with Queue • Depth=1, 2, 4, 8, 16, 32, 64, 128...

apps.apple.com

 

[kirkster501]

Ok, looking much better 24 hours after the fresh reinstall of Catalina. So clearly after the install, OSX is doing something pretty fundamental stuff to the disks still for multiple hours.

I will see if it improves further.

TBH, at those speeds on a late-2013 i5 with the 1TB fusion I am pretty happy and I am starting to question if it is worth the risk opening the machine up and spending $150+ on a new NVMe to improve to a max of 740/740 that the 2013 maxes out at.

I have a broken hinge so I may still do it. I am latest 480 boot as well so I'm all good to go should I choose to do it.

 

[Juicy Box]

If it ends up being that the BMDST shows improved speeds, but your disk still feels sluggish, try AmorphousDiskMark from the Mac Appstore. It is free, and give a much more "real world" test result of the performance of your drive.

Like I mentioned before, BMDST tests sequential only, while in the real world, we experience lots of small, random reads and writes.

I suspect that being on Catalina might skew the test results of BMDST even more since you are using a Fusion Drive with a HDD.

I am starting to question if it is worth the risk opening the machine up and spending $150+ on a new NVMe to improve to a max of 740/740 that the 2013 maxes out at.

If opening your Mac isn't something you want to do, or something you want to do now, just doing something external for now will give you a much better experience.

Even a SATA SSD over USB would probably give you a better experience. The BMDST wouldn't be as high, but the randoms

will definitely update the NVMe to a 2TB and stick a 8TB HDD in for mass storage.

I personally would never open my iMac and replace the HDD with another HDD.

Besides the fact of the higher failure rates of HDDs, the thermals are not great in the iMacs already, and having the hot mechanical drive removed could improve things.

If I really needed a boot drive that large, I would just use an internal SSD and create a Fusion Drive with the internal SSD and an external HDD.