iMac Late 2015 extremely slow

[tarat]

Hi, Mac (Retina 4K, 21.5-inch, Late 2015) -

3.1 GHz Quad-Core Intel Core i5 -

8 GB 1867 MHz DDR3

Has been slow, especially since Catalina. I keep everything up to date. it has ample memory left. I have removed anything from the start. It's still very slow, freeze, occasionally I get black screen and restart. Regularly I get messages that it cannot find the wireless keyboard or mouse. I gave up with he wireless mouse and use a wired one.
I dont do anything special with it, mostly internet browsing and some word processing.
I read threats suggesting external SSD. Would that be usable on my SATA HARD DRIVE docking station?
The issue is not limited the start. any operation is painfully slow.
Thanks for your help.

 

[4sallypat]

I use an external Thunderbolt SSD - my wife's iMac from 2013 uses the LaCie TB2 with SSD and runs circles around the internal slow spinning drive.

As a matter of fact, I am currently upgrading a friend's 27" 2013 iMac with the Transcend 512GB TB2 SSD and Catalina is super fast!

Using the internal HDD as a repository / archive / non speed files.

Let me know if you want to see pix...

 

[tarat]

I use an external Thunderbolt SSD - my wife's iMac from 2013 uses the LaCie TB2 with SSD and runs circles around the internal slow spinning drive.

As a matter of fact, I am currently upgrading a friend's 27" 2013 iMac with the Transcend 512GB TB2 SSD and Catalina is super fast!

Using the internal HDD as a repository / archive / non speed files.

Let me know if you want to see pix...

Yes, plz happy to see your pix.
Would this resolve the issue of slow surfing even apart fro the start ? like Wifi and not finding wireless keyboard.
Would I not need to re-install the machine before to make sure they are no other issues ?

 

[Juicy Box]

You have an internal HDD, correct?

I have read a lot of posts saying that Catalina is horrible on a HDD boot disk.

read threats suggesting external SSD. Would that be usable on my SATA HARD DRIVE docking station?

Probably, can you post which one it is?

MacOS boots well on external drives, and I have been doing for a very long time. Boots from TB, USB, and FW drives, even from thumb drives and SD cards.

You can even boot from old iPods.


SSD prices are dropping again, I saw a SATA3 1TB SSD for $80 on Best Buy yesterday.

You can use an external enclosure, or even a cheap SATA3 to USB3 adapter:

EYOOLD SATA to USB 3.0 Adapter Cable for 2.5 inch Hard Drive HDD/SSD Data Transfer, External Hard Drive Converter Support UASP (Black)

EYOOLD SATA to USB 3.0 Adapter Cable for 2.5 inch Hard Drive HDD/SSD Data Transfer, External Hard Drive Converter Support UASP (Black)

www.amazon.com

If your dock didn't work out, a TB enclosure would probably be the best choice, but is also pricey. You can't get TRIM support with USB for Mac, but even without TRIM, I am sure it would be much quicker than your HDD.

Using a NVMe over TB would probably be the fastest option, but also the most expensive, and probably overkill for what you need your Mac to do.

 

[4sallypat]

Yes, plz happy to see your pix.
Would this resolve the issue of slow surfing even apart fro the start ? like Wifi and not finding wireless keyboard.
Would I not need to re-install the machine before to make sure they are no other issues ?

Yes, using an external SSD is much faster than using the internal HDD.

I am not adept nor careful about opening up the iMac, so I opt for an external.
And I did not want to opt for the USB-3 drive even though it would be cheaper because the data throughput is half that of TB2.

Here is what I just did for my friend's 27" iMac:

This is what I used for my wife's 21.5" iMac:

 

[Fishrrman]

That has a platter-based hard drive inside, is this correct?

If so...
THE SOLUTION is to get a USB3 SSD, plug it in, and set it up to become the new boot drive.

This is fast, easy, cheap, and safe (you can open the iMac and install it inside, but it's a fairly complicated job with the risk of breaking something in the process).

You didn't tell us the size of the internal HDD.
If it's 1tb, you could get a 1tb SSD and use either CarbonCopyCloner or SuperDuper to "clone over" the contents of the internal drive to the SSD, which simplifies the process.
Both CCC and SD are FREE to download and use for 30 days, so doing this will cost you nothing.

You can buy a "ready-to-go" USB3 SSD like the Samsung t5.
Or, get a "bare" 2.5" SSD (I like Crucial or Sandisk), and put it into an enclosure like this one:

SABRENT 2.5 Inch SATA to USB 3.0 Tool Free External Hard Drive Enclosure [Optimized for SSD, Support UASP SATA III] Black (EC-UASP)

SABRENT 2.5 Inch SATA to USB 3.0 Tool Free External Hard Drive Enclosure [Optimized for SSD, Support UASP SATA III] Black (EC-UASP)

tinyurl.com

If the SATA dock you have is USB3, you could put it in there, too.
But the disadvantage is you won't be able to use the dock for OTHER drives while you're booted from the SSD...!

 

[killerrobot]

Is this true for the fusion drives? The SSD should be booting correct and not the HDD?

My 2015 has been beachballing and running all sorts of slow since Catalina (and there's a weird ethernet glitch that's limiting fiber to 200Mbs speeds instead of 1g). Not a fan of Catalina on 2015 machines.