Samsung ssd T5 and APFS write speed issues... Help!!

[JimCash]

Hello there! I bought a Samsung external SSD T5 to boot up my iMac 21"mid 2017 (this with internal HDD) to get faster. While I was in HFS+ this drive working just great around 520read/480write speeds which is normal good for USB-C (Gen2) interface ssd. BUT When (my bad) decided to format in APFS this drive get unstable. read/write speeds slightly decreased(most on write) about 50-100 write/400-450 read. So I decide to run back in HFS+. BUT unfortunately after the last format in HFS+ this drive get serious problem with write speed... So now I'm getting only 20-40 write speed in Blackmagic (worst than a simple hdd). For read speeds I've no problem its still good around 510-520. p.s. I formatted with disc utility. and measure in latest ver. Blackmagic and Xbench.
Also, it took about 4 min -maybe most- just to see the external drive and boot from there as in APFS formation.

Conclusion,
I think this is permanent and it somehow harmed the disc when converted.

Any advice will be good... =)

 

[h9826790]

Hello there! I bought a Samsung external SSD T5 to boot up my iMac 21"mid 2017 (this with internal HDD) to get faster. While I was in HFS+ this drive working just great around 520read/480write speeds which is normal good for USB-C (Gen2) interface ssd. BUT When (my bad) decided to format in APFS this drive get unstable. read/write speeds slightly decreased(most on write) about 50-100 write/400-450 read. So I decide to run back in HFS+. BUT unfortunately after the last format in HFS+ this drive get serious problem with write speed... So now I'm getting only 20-40 write speed in Blackmagic (worst than a simple hdd). For read speeds I've no problem its still good around 510-520. p.s. I formatted with disc utility. and measure in latest ver. Blackmagic and Xbench.
Also, it took about 4 min -maybe most- just to see the external drive and boot from there as in APFS formation.

Conclusion,
I think this is permanent and it somehow harmed the disc when converted.

Any advice will be good... =)

The slow writing most likely due to lack of TRIM support via USB.

If you want to recover the writing speed, you can secure erase your SSD. However, it will only help on the 1st write, once you write the whole SSD once. The writing speed will be affected again.

The build in over provision may allow GC to free up some space for fast write. But it takes time, and only limited free cells available. Every time you used up all free cells, the writing speed will be greatly affected. Until the SSD go back to idle, and GC can try to free up some cells again.

If you want to maintain relative good writing speed all the time. After you secure erase the whole SSD. Only use 80% of its total capacity to make a HFS+ partition, leave the remaining 20% untouch (never partitioned). So that the SSD controller can use this 20% "free space" as over provision as well. Which should greatly improve the sustain write performance.

 

[JimCash]

The slow writing most likely due to lack of TRIM support via USB.

Hmmmm very interesting.. But I think there s no trim support for this drive

 

[Mike Boreham]

Hmmmm very interesting.. But I think there s no trim support for this drive

My understanding also. TRIM command not sent to external USB on Macs. This article includes this statement:

"Previous versions of the Samsung Portable SSD did not support TRIM. The new T5 products accept the command from the host through the UASP protocol. The feature doesn’t work with the native exFAT file system that provides compatibility with Android and other devices. You will need to format the Portable SSD T5 with the NTFS file system for the feature to work."

This thread has a discussion about TRIM and externals on Macs.

I also have a Samsung T5 attached to my 2017 iMac and it is formatted APFS and read/write speeds are in the 400/500 range, so there is no basic problem with the T5 formatted APFS.

Have you tried simply formatting it in Disk Utility. You could use DU First Aid to check the Partition map by selecting the top drive level on the LHS. When using DU to format it sometimes fails the first time and succeeds on repeat. You may need to erase at volume (indented) and drive (top) level.

 

[JimCash]

My understanding also. TRIM command not sent to external USB on Macs. Have you tried simply formatting it in Disk Utility. You could use DU First Aid to check the Partition map by selecting the top drive level on the LHS. When using DU to format it sometimes fails the first time and succeeds on repeat. You may need to erase at volume (indented) and drive (top) level.

So. In my instance I’ve bought T5 to boot the Mac OS from there. There ar no so many ways to make this to work. Certainty for that reason I tried to format it in APFS to test if I could trim this drive cause in simple HFS+ couldn’t. Also as you read they say T5 support trim but only in NTFS (windows side). So I don’t think you can use TRIM function if you make-format T5 for using as boot drive for Mac OS.

Maybe you r write that you can trim it but when you don’t boot Os from this drive.

In my case when in APFS and run Mac OS HIGH SIERRA it was taken about 4 maybe more minutes after power on my iMac,and takes to long just to show the Apple icon and after that starting the booting sequence...But when re formatted in hfs+ run Os immediately. It’s certainly that something goes wrong if you run Os in AFPS formation in T5...

 

[h9826790]

It’s certainly that something goes wrong if you run Os in AFPS formation in T5...

I think it's not just the T5, but APFS is generally not up to standard yet (in terms of stability).

I use APFS for about 2 months, and finally downgrade back to HFS+. I rarely do any downgrade (as you can see, I still try it for 2 months), but this time, I am really happy with go back to HFS+. Especially I am a dual OS user, leave macOS in HFS+ is so much easier to switch between OS.

 

[Mike Boreham]

So. In my instance I’ve bought T5 to boot the Mac OS from there. There ar no so many ways to make this to work. Certainty for that reason I tried to format it in APFS to test if I could trim this drive cause in simple HFS+ couldn’t. Also as you read they say T5 support trim but only in NTFS (windows side). So I don’t think you can use TRIM function if you make-format T5 for using as boot drive for Mac OS.

Maybe you r write that you can trim it but when you don’t boot Os from this drive.

In my case when in APFS and run Mac OS HIGH SIERRA it was taken about 4 maybe more minutes after power on my iMac,and takes to long just to show the Apple icon and after that starting the booting sequence...But when re formatted in hfs+ run Os immediately. It’s certainly that something goes wrong if you run Os in AFPS formation in T5...

I still suggest you try reformatting it and starting from scratch. There is no reason for the T5 to be slow in APFS. Booting does sometimes take a long time especially first time.

All my SSD drives, internal on two Macs and external installations on T3s and T5 are APFS without problems although there are learning curves when using Disk Utility and if mixing HFS and APFS on the same drive.

I don't worry about TRIM much these days. SSD manufacturers have their own built garbage collection mechanisms which do the same job but maybe more slowly. The only time I have had a problem was with an early SSD which I would boot occasionally for short periods only. The garbage collection never had a chance to work (needs periods of machine idle).

 

[h9826790]

I still suggest you try reformatting it and starting from scratch. There is no reason for the T5 to be slow in APFS. Booting does sometimes take a long time especially first time.

All my SSD drives, internal on two Macs and external installations on T3s and T5 are APFS without problems although there are learning curves when using Disk Utility and if mixing HFS and APFS on the same drive.

I don't worry about TRIM much these days. SSD manufacturers have their own built garbage collection mechanisms which do the same job but maybe more slowly. The only time I have had a problem was with an early SSD which I would boot occasionally for short periods only. The garbage collection never had a chance to work (needs periods of machine idle).

GC is not the replacement of TRIM. It work with TRIM. Without TRIM, there will be no "available space" (except the build in over provisioning) for GC to move the data around. Therefore, the SDD will have much much less free cell ready for the next write (this is the reason of the low writing performance)

Also, without TRIM, GC have to move lots of useless data around (if over provisioning available). Which will greatly reduce the SSD's life span because of write amplification.

Even though I agree that SSD can work well without TRIM in general (because most user mainly need the random read performance, which is totally irrelevant to TRIM). And even without TRIM, a SSD can still last longer then the computer itself. But I still want to point out GC is not TRIM, they are totally different. TRIM is pretty much a OS level software functions, and GC is the hardware function. They can't replace each others. Without GC, TRIM is basically meaningless. Without TRIM, GC will be very inefficient.

This link has pretty good explanation. And it mentioned about that Samsung Filesystem-aware GC as well.

https://en.wikipedia.org/wiki/Write_amplification

 

[maflynn]

The slow writing most likely due to lack of TRIM support via USB.

That doesn't make sense. The idea is that the lack of TRIM will mean some SSDs will slow down over time. In the OP's case his performance drop was nearly instant. Also many SSDs currently employ their own garbage collection mechinisms, which largely mitigate the need for TRIM

 

[h9826790]

That doesn't make sense. The idea is that the lack of TRIM will mean some SSDs will slow down over time. In the OP's case his performance drop was nearly instant. Also many SSDs currently employ their own garbage collection mechinisms, which largely mitigate the need for TRIM

What OP did is actually perfectly fit this situation.

He format the SSD (not secure erase) without TRIM. So, all old data (in the controller's point of view) still there. And then the re-install the OS (writing more data in). This action most likely completely use up all the free cells which created by GC and the over provisioning.

Therefore, when he perform the benchmark, there is no more free cell available. The SSD controller has to free up the cell in real time. This process is very slow.

And if there is some background activity (e.g. indexing) because the newly installed OS. That can further worse the situation.

Without the help of TRIM, the SSD can only provide fast write when

1) it's new
2) after secure erase
3) after GC successfully free up some cells (with over provisioning)

OP's case is definitely not (1) and (2)

For (3), it takes time, I suspect if OP let his Mac idle for few hours (real idle for the SSD, no indexing in the background. Or simply boot into recovery partition. Or even just hold option during boot, and let the Mac stay at the boot manager) And then run the benchmark again. He may see an improvement. But if he keep running the benchmark, the writing speed will drop again.

If this happen, then almost 100% sure lack of TRIM is the primary cause of his slow write issue.

 

[Fishrrman]

OP:
My suggestions:

1. If there is any Samsung proprietary software (including a proprietary partition) on the t5 drive -- GET RID OF IT.

2. Erase the t5 to "Mac OS extended with journaling enabled" (Disk Utility should do this)

3. REinstall High Sierra onto the t5. I suggest you create a bootable USB flash drive installer, and boot the Mac using the flashdrive installer, and install that way. DO NOT do an "internet recovery install".

4. IF you are offered the option to do an APFS install, DO NOT do it if there is any way to "back out of it". Do the install as HFS+

5. See if you can get installed and running that way.

6. DO NOT attempt to enable TRIM via USB.

Actually, unless you absolutely, positively have-to-have High Sierra, I'd suggest Low Sierra instead. But then, if you want to keep bangin' your head against the wall with HS, be my guest!

 

[JimCash]

Yes obviously that’s it!!! In benchmarks from the beginning shows good speeds like 480mb/sec write - 520mb/sec read. But shortly after it’s going down 40mb/sec write speed. So it seams obviously lack of Trim.

So! Any suggestions how to trim this drive? Are there any way to activate trim while using this drive for booting MacOs HS ?

[doublepost=1518021491][/doublepost]

OP:
My suggestions:

1. If there is any Samsung proprietary software (including a proprietary partition) on the t5 drive -- GET RID OF IT.

2. Erase the t5 to "Mac OS extended with journaling enabled" (Disk Utility should do this)

3. REinstall High Sierra onto the t5. I suggest you create a bootable USB flash drive installer, and boot the Mac using the flashdrive installer, and install that way. DO NOT do an "internet recovery install".

4. IF you are offered the option to do an APFS install, DO NOT do it if there is any way to "back out of it". Do the install as HFS+

5. See if you can get installed and running that way.

6. DO NOT attempt to enable TRIM via USB.

I made exactly these steps (except the step 1.) and the problem in low write speeds still remains... as I wrote... I’ve the same good read speed but very low in write... it shortly goes down at 20/40 in benchs.

The drive is brand new about 3-4 days. Now I’m hfs+ the problem remains :-/

 

[MarckyG]

[doublepost=1518021491][/doublepost]

I made exactly these steps (except the step 1.) and the problem in low write speeds still remains... as I wrote... I’ve the same good read speed but very low in write... it shortly goes down at 20/40 in benchs.

The drive is brand new about 3-4 days. Now I’m hfs+ the problem remains :-/

Im sorry for the problems you’re having ... is there any update to the topic?
What has happened by now?

 

[JimCash]

Im sorry for the problems you’re having ... is there any update to the topic?
What has happened by now?

I made SAFE format(about 5 passes)and back to HFS and now works like a charm

 

[MarckyG]

So writing zeroes five times over the complete ssd while formatting? I hope that wasnt too much of a hit to the SSD lifetime.

 

[h9826790]

So writing zeroes five times over the complete ssd while formatting? I hope that wasnt too much of a hit to the SSD lifetime.

5 times just about 0.01% of the life span, shouldn't make any difference.

And if the SSD controller is smart enough. There may be no actual writing process when the file system ask to write a zero to a zeroed cell. I bet this process takes a long time just because there are lots of I/O request between the file system and the SSD, not because there are lots of actual "write" to each cell.

 

[MarckyG]

5 times just about 0.01% of the life span, shouldn't make any difference.

And if the SSD controller is smart enough. There may be no actual writing process when the file system ask to write a zero to a zeroed cell. I bet this process takes a long time just because there are lots of I/O request between the file system and the SSD, not because there are lots of actual "write" to each cell.

Okay thanks for the explanation, good to know this backup method would work in case if needed.

 

[bc007]

Samsung T5 packaging very deceptive - USB 3.1 Gen 2 - your CABLES can "plug into" the faster Apple ports but
you will only get USB speeds - nothing approaching 10 Gbps. The USB 3.1 gen 2 Apple port "interface" will reach those speeds but T5 ONLY supports basic USB speeds. Incredibly deceptive advertising. As of 6/2018 SanDisc is the only SSD that utilizes a Thunderbolt connection so if you want speed - we all do - I'd check our SanDisk's newest portable SSD. The tests on Tomshardware have it crushing the T5. I just bought the T5 an am now stuck with a basic "usb" speed SSD.

 

[Mike Boreham]

All protocols have theoretical max speeds way higher than the real world. No one expects USB2 devices to run a 480mbps (60MB/s).

The advertising I have seen for T5 claims 540 MB/s which is what it does.

 

[bc007]

All protocols have theoretical max speeds way higher than the real world. No one expects USB2 devices to run a 480mbps (60MB/s).

The advertising I have seen for T5 claims 540 MB/s which is what it does.

[doublepost=1529711525][/doublepost]

1. Samsung T5 - real simply - the SSD should say it comes with CABLES that work with USB3 and Thunderbolt connections but the SSD is a USB 1 ONLY device... NOT USB3 or T-bolt... If it was not for the "deceptive" advertising and marketing I would have simple bought the SanDisk which does support T-bolt. Given the unending layer of confusion over USB 3- Gen 2, Thunderblolt - Samsung "implies" it does it all when in fact they provide CABLES that work with those ports BUT the SSD only supports USB 1 protocols and speeds. HUGE difference... Obviously - you want speed and you have USB 3 and/or T-bolt - don't waste your time with T5 - simple go to SanDisk. In closing, I have innumerable Samsung internal SSD's and am a loyal user. I bought the T-5 for ONE reason - cuz they printed material says compatible with USB-B and Thunderbolt... The CABLES are compatible - the T-5 is OLD techology supporting USB 1 speeds ONLY...

 

[Mike Boreham]

[doublepost=1529711525][/doublepost]

1. Samsung T5 - real simply - the SSD should say it comes with CABLES that work with USB3 and Thunderbolt connections but the SSD is a USB 1 ONLY device... NOT USB3 or T-bolt... If it was not for the "deceptive" advertising and marketing I would have simple bought the SanDisk which does support T-bolt. Given the unending layer of confusion over USB 3- Gen 2, Thunderblolt - Samsung "implies" it does it all when in fact they provide CABLES that work with those ports BUT the SSD only supports USB 1 protocols and speeds. HUGE difference... Obviously - you want speed and you have USB 3 and/or T-bolt - don't waste your time with T5 - simple go to SanDisk. In closing, I have innumerable Samsung internal SSD's and am a loyal user. I bought the T-5 for ONE reason - cuz they printed material says compatible with USB-B and Thunderbolt... The CABLES are compatible - the T-5 is OLD techology supporting USB 1 speeds ONLY...

Samsung T5s are NOT USB 1 devices. They support USB 3,1 gen 2 and any quick speed test will give around 500 MB/s.
I have no idea why you would think they are USB 1 devices? Please post the rest result from your USB 1 T5. Here's mine:

 

[Joseph Fanarof]

#187
Heads up... I discovered that my Samsun 850 EVO SSD was giving a false positive after I cloned the internal drive using Super Duper. I fist formatted the drive to APFS then performed the clone process. Afterwords I selected the SSD as the boot drive in the system preferences. All seemed good however I wasn't happy with the speed of the new SSD. I verified the startup disk was indeed the new SSD and to double check I restarted the my iMac holding down the option key. When the boot window appeared the SSD wasn't present only the internal SATA. I then restarted an opened there disk utility and noticed I had the option to unmount the SSD. So curiously I unmounted the drive and to my amazement nothing happened other then my SSD disappearing from the desktop. I remounted the SSD and the drive reappeared.This proved that I was actually still accessing the internal drive regardless of the fact it clear wasn't the boot disk listed in the system preferences. So the remedy was disconnecting the SSD and then restarting my iMac while holding down the option key. Once the startup drive window appeared i then plugged the SSD drive in and "BINGO" the SSD showed up as a viable boot drive. After doing this I went from slow to super fast speeds as you would expect. I have a feeling there might be a substantial amount of Mac users doing the exact same procedure however the general blame seems to be focused on "High Sierra" and the transition from Extended Journal/Guid to APFS update. Hope this info helps others.

So I also purchased a Samsung T5 SSD today and used Super Duper to clone my 850 EVO External SSD to my new T5. I first formatted the SSD and noticed I wasn't presented with an v format so I used Mac OS Extended (Journaled). After completion and restarting I opened applications/startup and the T5 SSD wasn't listed only the internal SATA and the external 850 EVO SSD. So I restarted holding down the option key and I was presented with the internal SATA and fortunately the T5 SSD showed up as two drives Samsung_T5 and Windows. Not sure why the Windows drive was an option since I didn't get that option with the 850 EVO. However with the T5 I didn't need to disconnect the drive while restarting like I did with the 850 SSD. However the 850 SSD did show up as a valid startup disk unlike the T5. So after selecting the T5 option my iMac did successfully boot to the T5 drive. However when I checked the system preferences/startup the T5 drive wasn't present. I then opened applications/utilities/disk utilities and when I clicked on the T5 drive the option to unmount the this drive was greyed out which as least confirms the operating system (High Sierra) did boot correctly. I then restarted normally and it booted to my internal drive even though the startup drive indicates it's supposed to be the 850 EVO. Again this is a "false positive" which I believe is causing many users to complain about super slow SSD drives when in fact they are actually accessing their old internal drive. Again the work around is restarting with the SSD disconnected and holding down the option key. You then connect the SSD after you see the startup menu and it will instantly appear as a valid boot drive.

So the only difference in the SSD drives was the 850 EVO was formatted to APFS and the T5 was Mac OS Extended (Journaled). So I was curious to know if after cloning the new T5 if the disk utility would allow this drive to be formatted to APFS. Unfortunately when I clicked on the tab options the APFS format wasn't present. I then for whatever reason decided to hold down the control key while clicking on the T5 drive and sure enough I was presented with "Add APFS Volume".

So I was ready to reformat when I stumbled upon this YouTube link chichis probably the "Holy Grail" for any user who like myself is having difficulty cloning and booting an HDD/SSD in Mac's "High Sierra" operating system. Here is the link video

. I haven't tested any of this new knowledge but everything the moderator from CCC talked about was super relevant and important for any Mac user to know. Apple changed curtain function in the disk utility app that are major and easily misunderstood. I can't believe this information isn't included with every SSD or HDD sold that is Mac compatible for the latest operating system 10.13.6. I'm willing to bet this lack of understanding the updated functionality of the disk utility has created extreme hair pulling habits for an abundance of Mac Users.

I will report back after I complete the setup correctly as shown in the video link I posted above. Hopefully this will resolve the boot issues I'm experiencing.

 

[AndyPT]

Hello there! I bought a Samsung external SSD T5 to boot up my iMac 21"mid 2017 (this with internal HDD) to get faster. While I was in HFS+ this drive working just great around 520read/480write speeds which is normal good for USB-C (Gen2) interface ssd. BUT When (my bad) decided to format in APFS this drive get unstable. read/write speeds slightly decreased(most on write) about 50-100 write/400-450 read. So I decide to run back in HFS+. BUT unfortunately after the last format in HFS+ this drive get serious problem with write speed... So now I'm getting only 20-40 write speed in Blackmagic (worst than a simple hdd). For read speeds I've no problem its still good around 510-520. p.s. I formatted with disc utility. and measure in latest ver. Blackmagic and Xbench.
Also, it took about 4 min -maybe most- just to see the external drive and boot from there as in APFS formation.

Conclusion,
I think this is permanent and it somehow harmed the disc when converted.

Any advice will be good... =)

The following solution that worked for me. I'm using late 2013 iMac Mojave with regular 1Tb HDD that's got VERY slow despite only using 150Gb, so now trying to run whole system on Samsung 250gb T5 SDD. I formatted T5 as APFS and used Carbon Copy Clone ("CCC") to copy everything to the T5 and then set T5 as Startup Disk from Preferences. Boot time to Log In screen was snail-like 3-5 minutes with blank screen half that time! After raising the issue with Bombich Software (developers of CCC), eventually Mike Bombich himself suggested "You could boot back to the HDD, erase the entire T5 as HFS+, then clone the HDD --> SSD. Some people have reported that the HFS+ formatted T5 did not experience the startup delay. You can't install Mojave onto the T5 via the Mojave Installer without converting it to APFS, but you can clone your Mojave to an HFS+ formatted volume, and the format will not change." Tried that and Power On to login now 35 secs with log in and all apps loading instantly! So I'm thinking that whatever read/write speed issues were, going back to HFS+ in this way sorted them. Thank you Mike - great support and CCC is a great product!

 

[Eddy P]

Had this same issue with our T5 ssd and Mojave and yes, reformatting the whole thing back to HFS+ solved everything (for me). Unfortunately, not every co-reader didn't agree with my findings back then.... The ssd drive is running great now though !

 

[MarckyG]

With all the hassle about Mojave, APFS, and SSD speeds.. I have another oddity to report.
It's not about the T5 but about the SanDisk Extreme 900 (a 1,92TB SSD in Raid0).
While on my old Mac with Sierra and HFS+ the drive had normal speeds over USB3.0: around 420MB/s write and 450MB/s read.
Now with my new iMac, I was eager to test the actual speeds this drive can do with a USB-C Thunderbolt 3 connector...
250MB/s write and 850MB/s read.... WAIT WHAT? The USB 3.1 Gen2 protocol definitely let's the read speeds go to their full potential, but the write speeds suffer? And it's the same with USB-A cable or USB-C 3.1 Gen2 cable...
The read speeds go to around 400MB and after a second they drop to 300 and then stay at around 250MB/s...
I tested with Blackmagic Disk Speed test and a file copying while watching the timer confirmed that...
Going back to my old iMac with HFS+ the write speeds are again better over the USB-A cable...
Ideas?