This is how mine is mounted with some Velcro 1/2" adhesive dots (strips work as well):
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Resolved 2017 iMac 27" external SSD as boot drive?
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Hey
I have a late 2015 27" iMac. Since i think it's terribly slow with the fusion drive , i put a new Samsung T5 hooked up via USB 3 to it and booting from it.
However , the iMac regularly freezes with that , and the only thing i can do is hit the Power Button . This only happens with the Samsung T5. The File System is APFS.
Any clue what this can be ? or what i can do about that ?
Thanks in advance .
I have a late 2015 27" iMac. Since i think it's terribly slow with the fusion drive , i put a new Samsung T5 hooked up via USB 3 to it and booting from it.
However , the iMac regularly freezes with that , and the only thing i can do is hit the Power Button . This only happens with the Samsung T5. The File System is APFS.
Any clue what this can be ? or what i can do about that ?
Thanks in advance .
can I ask a similar but slightly more complicated version of the Op's question.
I now have a 2017 model with the 1tb fusion. before my 2011 model died (sniff) I had just bought a thunderbolt 1 256gb SSD.
should I :
1. pay €50 for a thunderbolt 3 to 1 adaptor (can I get cheaper than the apple one?) and use this?
2. sell it on ebay and buy a usb 3 or thunderbolt 3 drive.
tbh I'm happy, if the thunderbolt 1 drive would deliver faster than the internal fusion drive and theres not a huge difference to go to thunderbolt 3 or usb c/3.
I now have a 2017 model with the 1tb fusion. before my 2011 model died (sniff) I had just bought a thunderbolt 1 256gb SSD.
should I :
1. pay €50 for a thunderbolt 3 to 1 adaptor (can I get cheaper than the apple one?) and use this?
2. sell it on ebay and buy a usb 3 or thunderbolt 3 drive.
tbh I'm happy, if the thunderbolt 1 drive would deliver faster than the internal fusion drive and theres not a huge difference to go to thunderbolt 3 or usb c/3.
Germs wrote in #27 above:
"the iMac regularly freezes with that , and the only thing i can do is hit the Power Button . This only happens with the Samsung T5. The File System is APFS.
Any clue what this can be ? or what i can do about that ?"
It could be the OS is "putting the drive to sleep" on you, or perhaps trying to eject it.
I'll give my advice, you may or may not wish to take it.
I'd do this:
1. Back up the t5 to another drive using either CarbonCopyCloner or SuperDuper (you want a BOOTABLE backup). You want this drive to be "pre-formatted" to HFS+, NOT to APFS.
2. Erase the t5, this time format it to Mac OS extended with journaling enabled (HFS+ instead of APFS).
3. RESTORE from the cloned backup back to the t5
4. See how it runs in HFS+ (rather than APFS).
"the iMac regularly freezes with that , and the only thing i can do is hit the Power Button . This only happens with the Samsung T5. The File System is APFS.
Any clue what this can be ? or what i can do about that ?"
It could be the OS is "putting the drive to sleep" on you, or perhaps trying to eject it.
I'll give my advice, you may or may not wish to take it.
I'd do this:
1. Back up the t5 to another drive using either CarbonCopyCloner or SuperDuper (you want a BOOTABLE backup). You want this drive to be "pre-formatted" to HFS+, NOT to APFS.
2. Erase the t5, this time format it to Mac OS extended with journaling enabled (HFS+ instead of APFS).
3. RESTORE from the cloned backup back to the t5
4. See how it runs in HFS+ (rather than APFS).
Hi
i did that . still the same problem. It just freezes , and then the iMac restarts. and it's mostly happening when i'm working on the iMac , not when i wake it up or so.
HFS+ installed and the drive to sleep turned off.
Just popping in to thank you all for a very informative thread. My 2013 21.5" iMac was feeling extremely sluggish for about 2 months or so. I just ran some diagnostics the other day, and the three diags all reported that the internal drive had failed S.M.A.R.T. tests. I bought a new iMac and transferred my data and apps over, but I wanted to continue to use that old iMac for less critical purposes.
I bought a 250GB USB 3.0 Sandisk SSD "pendant" (reminds me of the Amazon Fire TV) and cloned my old system to it and now use it to boot from. It now serves as my Plex Server (I've another external hard drive with all of my media).
I was quite surprised, even stunned, at the performance (boot up and operation) of using this drive. It's terrific. Maybe it's playing tricks on me, but it feels faster than the new iMac.
I have a question for others who have been using an external USB SSD on their iMacs...
What is the life expectancy of the drive when using it in this manner?
I bought a 250GB USB 3.0 Sandisk SSD "pendant" (reminds me of the Amazon Fire TV) and cloned my old system to it and now use it to boot from. It now serves as my Plex Server (I've another external hard drive with all of my media).
I was quite surprised, even stunned, at the performance (boot up and operation) of using this drive. It's terrific. Maybe it's playing tricks on me, but it feels faster than the new iMac.
I have a question for others who have been using an external USB SSD on their iMacs...
What is the life expectancy of the drive when using it in this manner?
That's an open ended question. It depends on how much writing you do to it and the model of SSD of course.
If you are using a larger, high quality SSD, and aren't using it to overwrite the drive completely on a daily or weekly basis, the life should be measured in years, not months. I used a 256GB Samsung 840EVO (a budget drive) for a couple of years as my late-2012 iMac boot drive, then upgraded it to a Toshiba 512GB drive for another couple of years, and both drives are still fine today.
Now, if you start using crappy no-name SSDs and they are small and you are writing a lot (thus using up many "drive writes per week", i.e. writing multiples of the drive capacity weekly) then I would expect the drive to give up the ghost pretty quickly.
YMMV.
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edited later --- correction, 250GB Samsung EVO.
Last edited:
Thanks! That's what I suspected, but I like to hear from real-word experiences. My uncertainty was focused primarily on the USB nature of the external SSD. I wasn't sure if the operating system interacts with an external SSD drive differently than an internal one. If there's no difference, then I would expect the lifespan to be equivalent to that of an internal SSD under similar load profiles.
Well, USB does tend to use lower block sizes, but if they are sequential then it shouldn't matter much. So a large block write that stays large on SATA may get broken up into several smaller sequential USB writes but since they are sequential, it shouldn't matter (much!)
I have an iMac 2017 with a 1TB fusion drive with macos and windows 10 dual boot using boot camp.
Windows boot is really slow because it doesn’t use any of the fusion stuff.
So I would buy a Samsung T5 (USB 3.1) and boot from the SSD but I have some questions that I was hoping you guys could help me.
Will this be slower than installing the SSD internally considering the top theoretical speed is 540m?
Will I be able to install both Windows and MacOS on the same external SSD and boot from it like I do on the internal drive? I read somewhere that this was only supported on thunderbold drives and in other cases Bootcamp would only install Windows on the internal drive.
Will the external drive support TRIM?
Thanks
Windows boot is really slow because it doesn’t use any of the fusion stuff.
So I would buy a Samsung T5 (USB 3.1) and boot from the SSD but I have some questions that I was hoping you guys could help me.
Will this be slower than installing the SSD internally considering the top theoretical speed is 540m?
Will I be able to install both Windows and MacOS on the same external SSD and boot from it like I do on the internal drive? I read somewhere that this was only supported on thunderbold drives and in other cases Bootcamp would only install Windows on the internal drive.
Will the external drive support TRIM?
Thanks
There's no support for Boot Camp on external drive.
There's also no support for TRIM on external drive.
I replaced a hard drive in my iMac with an SSD and recommend that.
https://forums.macrumors.com/threads/imac-27-inch-late-2013-hdd-ssd-upgrade.2122595/
I had the same issue with APFS, reformatted the Samsung T5 to HFS+, cloned high sierra from my HDD and now everything seems to be working smoothly.
The only thing i am currently struggling with is unmounting the internal HDD in order to reduce noise.
Is there an easy way to do that?
Digital Jockey asked:
"So I would buy a Samsung T5 (USB 3.1) and boot from the SSD but I have some questions that I was hoping you guys could help me.
Will this be slower than installing the SSD internally considering the top theoretical speed is 540m?"
You'll probably see speeds that are about 85% of what you'd see if the drive was installed internally.
BUT... going with an external boot drive eliminates the risk that you might break something when prying open the iMac to do an internal install.
It's a worthwhile tradeoff, in my estimation. The fastest, easiest, safest way to get a very impressive speed boost.
"Will I be able to install both Windows and MacOS on the same external SSD and boot from it like I do on the internal drive? I read somewhere that this was only supported on thunderbold drives and in other cases Bootcamp would only install Windows on the internal drive."
I don't use Bootcamp. I have read that it's possible to install BC on an external USB3 SSD, but the installation is an involved process. Can't help further.
However -- I would suggest that you consider "an emulation alternative" instead of BC.
"Will the external drive support TRIM?"
No, but TRIM is unimportant, anyway. Keep about 15% "free space" on the drive, and I predict you'll see little to no performance slowdowns for quite some time.
"So I would buy a Samsung T5 (USB 3.1) and boot from the SSD but I have some questions that I was hoping you guys could help me.
Will this be slower than installing the SSD internally considering the top theoretical speed is 540m?"
You'll probably see speeds that are about 85% of what you'd see if the drive was installed internally.
BUT... going with an external boot drive eliminates the risk that you might break something when prying open the iMac to do an internal install.
It's a worthwhile tradeoff, in my estimation. The fastest, easiest, safest way to get a very impressive speed boost.
"Will I be able to install both Windows and MacOS on the same external SSD and boot from it like I do on the internal drive? I read somewhere that this was only supported on thunderbold drives and in other cases Bootcamp would only install Windows on the internal drive."
I don't use Bootcamp. I have read that it's possible to install BC on an external USB3 SSD, but the installation is an involved process. Can't help further.
However -- I would suggest that you consider "an emulation alternative" instead of BC.
"Will the external drive support TRIM?"
No, but TRIM is unimportant, anyway. Keep about 15% "free space" on the drive, and I predict you'll see little to no performance slowdowns for quite some time.
I'm experiencing some pretty slow boot times with an external SSD formatted AFPS. So it's possible to use SuperDuper or Carbon Copy to clone AFPS to an HFS+ drive? At one point I tried to do a Time Machine restore from AFPS to HFS+ and got an error message.
davea wrote:
"I'm experiencing some pretty slow boot times with an external SSD formatted AFPS. So it's possible to use SuperDuper or Carbon Copy to clone AFPS to an HFS+ drive?"
I don't use APFS, but I believe the answer is yes, you can.
Do you have a spare external drive around?
If so, why don't you try it and get back to us with your experience...?
"I'm experiencing some pretty slow boot times with an external SSD formatted AFPS. So it's possible to use SuperDuper or Carbon Copy to clone AFPS to an HFS+ drive?"
I don't use APFS, but I believe the answer is yes, you can.
Do you have a spare external drive around?
If so, why don't you try it and get back to us with your experience...?
This is a really interesting thread. I am having a similar problem, but on an older machine. I have a 2011 iMac, and when trying to upgrade to High Sierra got a S.M.A.R.T. warning. I'm not in a position to upgrade the machine right now (I'm living abroad and the cost here is double), plus this isn't a work machine. I just need to keep it running till 2021 for some light Microsoft Office stuff, internet browsing, etc.
As this machine doesn't have USB3, would I be able to buy an external thunderbolt drive like this:
https://www.amazon.com/LaCie-Rugged...8&qid=1530839544&sr=8-4&keywords=lacie+rugged
And boot straight off that? Is there a better way of doing this? Any advice very gratefully received!
As this machine doesn't have USB3, would I be able to buy an external thunderbolt drive like this:
https://www.amazon.com/LaCie-Rugged...8&qid=1530839544&sr=8-4&keywords=lacie+rugged
And boot straight off that? Is there a better way of doing this? Any advice very gratefully received!
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I have used the LaCie Rugged Thunderbolt drives/enclosures in the past with good success. There used to be a good supply of refurbished 1TB drives available at low cost which I used to replace (very easy to do) the hard drive with a SSD and then used them for bootable Windows drives on my iMac. Then I just velcro mounted them to the back of the iMac stand. Worked great!
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banda wrote:
"Mine is so much faster now with Samsung T5.
The only issue I have is not seeing an external drive in the default start up disc option in system preferences."
Hmmm... sumthin' ain't right here.
You're saying you can boot from the t5, but it doesn't show in the startup disk pref pane AT ALL?
Take a screenshot and post the pic so we can all see what you're seeing.
My first thought is:
- Go to the finder
- Choose "about this Mac" from the Apple menu
- It tells you from which drive you are booted. Does it indicate the t5?
"Mine is so much faster now with Samsung T5.
The only issue I have is not seeing an external drive in the default start up disc option in system preferences."
Hmmm... sumthin' ain't right here.
You're saying you can boot from the t5, but it doesn't show in the startup disk pref pane AT ALL?
Take a screenshot and post the pic so we can all see what you're seeing.
My first thought is:
- Go to the finder
- Choose "about this Mac" from the Apple menu
- It tells you from which drive you are booted. Does it indicate the t5?
The quick dirty answer is that APFS DOES do a smart check on drives at boot time. The pause is for retries to verify. It reties until it fails and then proceeds with boot. It is annoying and it is a side effect of smart not being supported in usb 2/3/c as yet (though it does not affect Mojave builds from DP5 as I've been able to tell - but it still can change the same way fusion support was pulled at the last second from High Sierra) The only drives that don't suffer from it are TB3 right now (that includes both SSD and spinning drives) Wish I could recommend a workaround but it's up to apple to compromise on that - probably not a good idea because of how APFS is setup in it's current form.
I like Drive DX to c heck external drives as they are so important. Only $20.
https://binaryfruit.com/drivedx/usb-drive-support
https://binaryfruit.com/drivedx/usb-drive-support
MacOS SSD 500GB is the name I gave the T5. I choose it when holding option on start up, but want to make it the default startup drive when I restart or turn on computer.
Here is the screen shots