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imac9556

macrumors 6502a
Original poster
Jul 12, 2004
573
30
I recently got a "new" Apple iMac 21.5" 4k (3.0 i5/1TB/8GB) from a friend for a great price! It was only 4 months old but he needed to upgrade to the larger 27" iMac because of sight issues. My previous iMac back in 1999 was red, G3 333Mhz, 32MB of RAM, and 6 GB hard drive. Since then I have been using a mix of PCs, Macs, and lately, a 2017 MacBook Pro work laptop with a 256GB SSD.
Screen Shot 2020-04-04 at 7.42.27 PM.png

Back to the iMac...wow how have things changed! The Retina display is gorgeous and form factor is aesthetically simple and pleasing. Very fast now-see below. Everything I would expect from Apple.

Now to the bad....as many of you experienced, I cannot believe that Apple is still using a spinning platter 5400RPM hard drives in these machines! Granted, this is not a CTO build, nor the bottom of the barrel non-4k model. But what a bottleneck and limiting factor in these machines! It is so disappointing...It isn't a cheap Mac either! I get spinning beach balls doing simple commands like opening system preferences and safari. Opening Apple Mail and loading all my messages takes at least 30 seconds, don't get me started on opening Microsoft Word, Excel, or Powerpoint! It takes a good 50 seconds to one minute! I went to bed last night unhappy about my purchase....

At first I was thinking something is wrong with this machine and something is broken. After looking on these forums, it seems like everyone else has similar experiences. Options include 1) Returning the iMac (which isn't possible for me) 2) Tearing apart the iMac and installing a SSD (which I did not want to void the 3 year AppleCare warranty) 3) Getting a ThunderBolt 3 external drive (a little expensive) 4) Getting a USB-C NVMe type of external drive.
I chose option 4: I got the Crucial X8 500GB USB-C Drive for $79 from my local MicroCenter. I used some 3M Extreme Fasteners (basically velcro on plastic steroids) to mount the drive on the upper stand between the iMac body and stand. It is very well hidden and you do not even notice it!
Screen Shot 2020-04-04 at 7.42.14 PM.png
Screen Shot 2020-04-04 at 7.43.49 PM.png
Screen Shot 2020-04-04 at 7.43.56 PM.png

The difference is NIGHT and DAY. The iMac runs like new and how it should be. Applications and basic functions run as fast, if not faster than my work MacBook Pro. I did a fresh install of Mac OS Catalina to the external drive and started anew (again). So I have performed two fresh installs in the last 24 hours (haha).

I created an Automator Action to automatically unmount the internal hard drive upon startup.

I hope that Apple reads these forums and removes the old 5400rpm hard drive in their future iMac models. I just looked at their website and in 2021, they are still selling the refreshed iMac 4k with the same old 5400rpm hard drive! Unbelievable!!

Anyways thank you everyone for your suggestions and help. Once the warranty expires I plan to install an internal SSD and max out the memory. It looks like the guides online are very detailed for this to happen. I just have to buy new screen adhesives apparently to glue the iMac back together to the glass pane. I wonder how much faster an internal SSD would be compared to my solution. Maxing out the memory might help too. I even noticed that the processor is removable and possibly upgradable.

Any other suggestions and mods? I am all ears
 

Fishrrman

macrumors Core
Feb 20, 2009
21,749
7,960
OP:

You did the right thing with the USB3.1 gen2 drive.
Have you run benchmarks on it yet?
Use the free "Blackmagic Speed Test" software at the App Store.

I have a USB3.1 gen2 drive I put together myself, and get reads in the 965MBps range with it.

Having said that, you wrote:
"Once the warranty expires I plan to install an internal SSD and max out the memory."

No, I don't think you want to do this, because the internal drive uses a SATA connection, which will probably be significantly SLOWER than you're getting with a proper USB3.1 gen2 connection as above.

If the 21" iMac also has a PCIe connector for a "blade SSD", THEN it might be worth doing. But NOT if the only internal connector is SATA.
 
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imac9556

macrumors 6502a
Original poster
Jul 12, 2004
573
30
Absolutely right to use external SSD. My only (mild) criticism is that you may have placed it in the hot airflow. I would put it below the O in the stand - or high up on the outside.

Thanks! I might move it down some...the drive sometimes is hot to the touch. SSDs do slow down when it gets hot correct?

Fishrrman
: That is interesting...I did not know that. How much performance decrease for SATA vs USB-C or Thunderbolt 3? I do not think my iMac has the PCIe connector since it only came with that 5400RPM 1TB HDD.

Here are my results too:
DiskSpeedTest.png
 
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Fishrrman

macrumors Core
Feb 20, 2009
21,749
7,960
In my experience, the blade drive I use in my USB3.1 gen2 enclosure will become quite hot with heavy usage. I think that's par for the course with the nvme blades used in these things.

On the other hand, all of my SATA SSD's stay cool to the touch all day...
 
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mj_

macrumors 65816
May 18, 2017
1,303
911
Austin, TX
How much performance decrease for SATA vs USB-C or Thunderbolt 3? I do not think my iMac has the PCIe connector since it only came with that 5400RPM 1TB HDD.
SATA: 6 Gbps
USB 3.0 or 3.1 Gen 1: 5 Gbps
USB 3.1 Gen 2 or USB 3.2: 10 Gbps

You'd be effectively cutting your current SSD performance in half by replacing the external USB 3.1 Gen 2 SSD with an internal SATA SSD.
 
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imac9556

macrumors 6502a
Original poster
Jul 12, 2004
573
30
SATA: 6 Gbps
USB 3.0 or 3.1 Gen 1: 5 Gbps
USB 3.1 Gen 2 or USB 3.2: 10 Gbps

You'd be effectively cutting your current SSD performance in half by replacing the external USB 3.1 Gen 2 SSD with an internal SATA SSD.

Thanks for the clarification! I am assuming USB that is 5 Gbps is USB-C and the 10 GBps is thunderbolt 3?
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Absolutely right to use external SSD. My only (mild) criticism is that you may have placed it in the hot airflow. I would put it below the O in the stand - or high up on the outside.

Thanks! I agree. The SSD got very got after some use. So I moved it to below the vent on the actual iMac itself!
F7641984-7E87-4EA3-A654-A7C6560C74D0.jpeg
 
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mj_

macrumors 65816
May 18, 2017
1,303
911
Austin, TX
No. USB-C is just a form factor and can carry anything from USB 1.1 to USB 3.2. Thunderbolt 3 is a completely separate protocol that uses the USB-C connector and carries a USB signal in addition to many other signals (such as DisplayPort). Thunderbolt 3 is also 4x as fast as USB 3.2 and can transfer up to 40 Gbps.
 
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imac9556

macrumors 6502a
Original poster
Jul 12, 2004
573
30
No. USB-C is just a form factor and can carry anything from USB 1.1 to USB 3.2. Thunderbolt 3 is a completely separate protocol that uses the USB-C connector and carries a USB signal in addition to many other signals (such as DisplayPort). Thunderbolt 3 is also 4x as fast as USB 3.2 and can transfer up to 40 Gbps.

Thank you for the education! So in theory once my current solution feels "slow" I can get a thunderbolt 3 external NVMe SSD and get up to 40 Gbps transfers if the hardware supports it. Way faster than replacing the internal HDD solution and my current solution of the USB 3.1 Crucial nvme. Is this Thunderbolt 3 solution as fast as if I had the iMac that has the fusion drive with the nvme slot and chose to take apart the iMac and replaced the SSD?
 
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mj_

macrumors 65816
May 18, 2017
1,303
911
Austin, TX
Yes, in theory you could get a Thunderbolt 3 enclosure and an NVMe SSD to utilize the full 40 Gbps bandwidth of your Thunderbolt 3 bus. However, you will not be able to feel any difference between a 10 Gbps SSD and a 40 Gbps SSD (that doesn't even exist yet, I think the fastest currently available SSD tops out at around 20 Gbps). Heck, most people won't be able to tell a SATA SSD and an NVMe SSD apart because it's not the peak sequential performance that matters but random 4K read/write. That's where spinning drives really falter.

In other words: your current setup is perfect. If it works for you and you don't run into any issues than stick with it until you either run out of disk space or your iMac falls apart.
 
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theluggage

macrumors 603
Jul 29, 2011
5,103
4,132
No. USB-C is just a form factor and can carry anything from USB 1.1 to USB 3.2. Thunderbolt 3 is a completely separate protocol that uses the USB-C connector and carries a USB signal in addition to many other signals (such as DisplayPort). Thunderbolt 3 is also 4x as fast as USB 3.2 and can transfer up to 40 Gbps.

(a) In reality "USB-C" often gets used to describe a device or cable that supports USB1/2/3.x and DisplayPort but not Thunderbolt. E.g. a USB-C dock vs, a Thunderbolt 3 dock. It may be pedantically correct, but there is no snappy name for "USB1/2/3.x and DisplayPort but not TB3"... In terms of speed, though, so-called ""USB-C"" isn't any faster than USB 3.1 (10Gbps USB 3.1g2 actually works over old-school USB cables, too).


(b) Thunderbolt 3 doesn't "carry a USB signal" - it carries PCIe and DisplayPort signals moshed together to share a single pair of wires. TB3 Docks/hubs etc. with USB 'ports contain a PCIe USB adapter (in principle the same sort of adapter that you'd plug into a Mac Pro to get extra USB ports). (except... USB-C cables have a separate pair of wires for 'legacy' USB 1/2 signals but I haven't heard of any Thunderbolt device using that...)

(c) Not a correction, but to be clear there are two totally different ways of sending DisplayPort down a USB-C cable - the "USB-C" way physically allocates some or all of the wires in the cable to DisplayPort signals and can drive a DisplayPort monitor with a relatively simple adapter - but a 4k@60Hz DP1.2 display needs all 4 high-speed pairs in a USB-C cable leaving nothing for USB3. The "Thunderbolt" way encodes two DisplayPort streams in the TB3 signal, so DP and PCIe can share the same wires - which is more efficient, but needs a dock or 'thunderbolt display' with a TB3 controller chip to extract the displayPort signals.

(d) To be picky, USB 3.2 can go up to 20 Gbps by combining 2 USB 3.1 connections (USB-C cables have 4 high-speed pairs, but USB 3 only uses 2 of them at a time) but, again, I haven't heard of anything that actually does that. May be an abandoned protocol with USB4 coming along.

...and if that is confusing, just wait until USB4 arrives... its sort-of TB3 without the brand name... except it's not quite the same and may or may not work with existing TB3 devices and if the USBIF does their usual and rebadges all the older USB protocols as USB4-something then.... arrgggh!

...but, bottom line... USB 3.1g2 (10Gbps) is already faster than most SSDs (and will smoke any mechanical drive). In a perfect world, I'd go TB3 just to make sure that the drive supported TRIM (without which performance can drop over time) - last I looked, USB on Mac still didn't support TRIM even with drives that support it on Windows.
 
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DCIFRTHS

macrumors 65816
Jan 25, 2008
1,078
502
...but, bottom line... USB 3.1g2 (10Gbps) is already faster than most SSDs (and will smoke any mechanical drive). In a perfect world, I'd go TB3 just to make sure that the drive supported TRIM (without which performance can drop over time) - last I looked, USB on Mac still didn't support TRIM even with drives that support it on Windows.

TBe supports trim commands from macOS without any additional drivers, or terminal commands?
 
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imac9556

macrumors 6502a
Original poster
Jul 12, 2004
573
30
I need some help...I don't know if I should create a new post but Ill first post here. I tried googling and searching on MacRumors forums but a ton of posts are old.
Does anyone have a way to unmount the internal hard drive at startup or script? Somehow I can hear the internal HDD spinning up during sleep or use of the computer even though the internal hard drive has been ejected (by dragging it to the trash) Understandably, at reboot the internal hard drive is remounted.
 
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BigMcGuire

Contributor
Jan 10, 2012
7,246
8,915
the Alpha Quadrant
That's how I ran my 2014 Mac Mini --- external USB 3 drive - for many years. I cannot believe anything over $1k being sold today has a spinner in it.

I just left the internal drive there because it had the recovery partition which I found handy to reinstall Mac OS when I wanted to. I never heard the drive in the Mac Mini but that may be because the fans were always pretty loud. It would drive me nuts if I could hear that spinning up and down all the time.

I build a screaming fast gaming PC last month for UNDER $1300 and I have TWO NVME drives 1TB with 64GB of 3200 ram. Yeah, I know it isn't Apple but... come on...
 
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retta283

Cancelled
Jun 8, 2018
2,658
2,658
Victoria, British Columbia
The 5400 RPM drive is laughable in 2020. It was laughable in 2012 as well. iMacs always had 7200RPM drives, going back to the G4 days. Even the $999 education 17-inch iMac had a 7200RPM drive.

I think your current setup is fine, any speed boosts you could gain with another method probably would not be worth the money/effort required.
 
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Fishrrman

macrumors Core
Feb 20, 2009
21,749
7,960
OP wrote:
"Does anyone have a way to unmount the internal hard drive at startup or script? Somehow I can hear the internal HDD spinning up during sleep or use of the computer even though the internal hard drive has been ejected (by dragging it to the trash) Understandably, at reboot the internal hard drive is remounted."

Here's a workaround.
It's not perfect, but it may work for you.
It costs nothing and if you don't like the results, just trash it.

Download the small free app called "Semulov" from here:

When you run it, it puts a small icon in your menu bar (on the right). You can set it so that Semulov runs on bootup.

Semulov allows you to dismount and mount drives and partitions.
Reach up and DISmount your internal drive.
Does it then "spin down"?

I believe you may have to do this once with each reboot.
Again, it's only "a workaround".
But it's better than nothing at all.
 
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imac9556

macrumors 6502a
Original poster
Jul 12, 2004
573
30
OP wrote:
"Does anyone have a way to unmount the internal hard drive at startup or script? Somehow I can hear the internal HDD spinning up during sleep or use of the computer even though the internal hard drive has been ejected (by dragging it to the trash) Understandably, at reboot the internal hard drive is remounted."

Here's a workaround.
It's not perfect, but it may work for you.
It costs nothing and if you don't like the results, just trash it.

Download the small free app called "Semulov" from here:

When you run it, it puts a small icon in your menu bar (on the right). You can set it so that Semulov runs on bootup.

Semulov allows you to dismount and mount drives and partitions.
Reach up and DISmount your internal drive.
Does it then "spin down"?

I believe you may have to do this once with each reboot.
Again, it's only "a workaround".
But it's better than nothing at all.

Thank you! So this software is different than just dragging "Macintosh HD" to the trash to eject it? It actually dis-mounts the drive
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I also have been searching and found some information writing a .command using terminal's diskutil.

Using text edit I created this .command that will run as a startup item.

Code:
diskutil eject '/dev/disk0'
diskutil eject '/dev/disk1'
Killall Terminal

Is this as effective as the software above? eject vs. unmount...I am struggling to figure out a difference
 
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