Stable write/read speed - external or internal SSD?

[HaykD]

Hi everyone!

I am doing SEO audits on my iMac 2020, so it is busy with writing data to SSD almost every day. Till now I was using Samsung T7 (500GB) drives via thunderbolt and they had good speed at the start. However, now I see the write speed drastically dropped, and it is very bad for the job described. Recently I was going to order Sabrent Rocket XTRM-Q 2TB USB 3.2 / Thunderbolt 3 External SSD for faster speed and more storage, but now, after checking T7's speed I am worried if its speed will drop too after some months of usage. So please advise - for stable write/read speed - should I continue using these external SSDs (in that case which brand will you suggest) or I should go with an internal SSD solution (which type, which brand, which adapter, please suggest). The port I am going to use is TB3.

Thanks in advance.

 

[Fishrrman]

Is this a 2020 27" iMac?
If so, did it not come with an internal SSD already installed?

 

[Boyd01]

I have three 2tb Samsung T7's for my 2018 Mini. I purchased two of them over a year ago, one for storing GIS data (for making maps) and the other as a Carbon Copy backup drive. The GIS drive has seen some heavy use, for example, I have made a number of high resolution maps for my website that consist of tiled data - literally several million 256x256 pixel PNG and JPG files in complex directory structures with thousands of directories.

Just tested that drive and it performs exactly the same as when it was brand new - write speed about 840 MB/sec and read about 920 MB/sec. Also tested my CCC backup drive, and that has actually slowed down significantly - about 460 write/870 read. That drive has been hammered on pretty hard for over a year with clones of my internal 2tb SSD that only has about 500gb free space.

My third 2tb T7 is less than a month old and is only used for a 1tb Final Cut Pro library of a current video project. It is also very fast ~840/920 like the other T7. Don't know if any of this helps. I am certainly not seeing write speeds nearly as low as yours. What capacity drive do you have? The smaller ones have slower write speeds, but that seems really extreme in your case, that's much slower than a 5400RPM hard disk!

 

[HaykD]

Is this a 2020 27" iMac?
If so, did it not come with an internal SSD already installed?

Yes, it is iMac 2020. It comes with SSD, 512 GB, but I needed more.

I have three 2tb Samsung T7's for my 2018 Mini. I purchased two of them over a year ago, one for storing GIS data (for making maps) and the other as a Carbon Copy backup drive. The GIS drive has seen some heavy use, for example, I have made a number of high resolution maps for my website that consist of tiled data - literally several million 256x256 pixel PNG and JPG files in complex directory structures with thousands of directories.

Just tested that drive and it performs exactly the same as when it was brand new - write speed about 840 MB/sec and read about 920 MB/sec. Also tested my CCC backup drive, and that has actually slowed down significantly - about 460 write/870 read. That drive has been hammered on pretty hard for over a year with clones of my internal 2tb SSD that only has about 500gb free space.

My third 2tb T7 is less than a month old and is only used for a 1tb Final Cut Pro library of a current video project. It is also very fast ~840/920 like the other T7. Don't know if any of this helps. I am certainly not seeing write speeds nearly as low as yours. What capacity drive do you have? The smaller ones have slower write speeds, but that seems really extreme in your case, that's much slower than a 5400RPM hard disk!

Mines are 500 GB, both have around 200GB free space, formats - ExFAT, Mac OS Extended (Journaled) (was required for software having an issue with ExFAT). The only difference I see comparing with your drives is the storage, also I have them connected to iMac all the time, I only disconnected them 2-3 times, could this be an issue? Purchase dates - January 13, 2021, February 8, 2021.

 

[Boyd01]

The "GIS disk" was purchased in June 2020 and has never been disconnected from my Mac, read/write speeds excellent - same as new. One difference is that all my SSD's are formatted as APFS. I use Windows GIS software but run it in a Parallels VM, so disk format is irrelevant.

My "CCC disk" was also purchased June 2020 but is only connected during backups and it has taken a big performance hit. Lots of big files on my internal SSD and also 3 VM's, so any time a single byte changes, a whole virtual disk needs to be copied in the CCC backup. It is also APFS formatted.

 

[hobowankenobi]

Could be a few things, including the cable or bus. There is some automated caching going on too...that can really slow down very large transfers.

And to be clear, these are USB 3.2 (C), which shares the same port as Thunderbolt 3. Confusing.

While it is possible to buy actual TB 3 external drives, they cost substantially more than any USB drive, and there are fewer options. I have not used this drive, but an example of an actual TB external.

I like the idea of roll your own, but again, I can't vouch for this model.

 

[HaykD]

I am considering buying a dual encloser with TB3 (it seems to be TB3) Sabrent Thunderbolt 3 To Dual NVMe M.2 SSD Tool-Free Enclosure (EC-T3DN) | EC-T3DN and any NVMe M2 internal SSD like Sabrent Rocket Q 2TB NVMe PCIe M.2 2280 Internal SSD Solid State Drive (SB-RKTQ-2TB) | SB-RKTQ-2TB Is there a chance the internal SSD like this or a Samsung, WD or another one will slow down the same way at some point?

 

[hobowankenobi]

I am considering buying a dual encloser with TB3 (it seems to be TB3) Sabrent Thunderbolt 3 To Dual NVMe M.2 SSD Tool-Free Enclosure (EC-T3DN) | EC-T3DN and any NVMe M2 internal SSD like Sabrent Rocket Q 2TB NVMe PCIe M.2 2280 Internal SSD Solid State Drive (SB-RKTQ-2TB) | SB-RKTQ-2TB Is there a chance the internal SSD like this or a Samsung, WD or another one will slow down the same way at some point?

That's a good question. The right one to ask.

I don't have an answer...but I would suggest at least finding a good hardware review of the model(s) in question. There are a handful of good review sites that really test and document components. Not sure I would trust a rando on the interwebs to really know. ?

Some of the biggest memory fab shops build the actual chips for others (Micron, Nanya, Hynix) but don't sell direct under their own names. Samsung is one of the only exceptions, and Micron sells direct as the brand Crucial. Always hard to know whose RAM you are getting and what the specs and performance will be without some serious benchmarking.

 

[HaykD]

The "GIS disk" was purchased in June 2020 and has never been disconnected from my Mac, read/write speeds excellent - same as new. One difference is that all my SSD's are formatted as APFS. I use Windows GIS software but run it in a Parallels VM, so disk format is irrelevant.

My "CCC disk" was also purchased June 2020 but is only connected during backups and it has taken a big performance hit. Lots of big files on my internal SSD and also 3 VM's, so any time a single byte changes, a whole virtual disk needs to be copied in the CCC backup. It is also APFS formatted.

Converted one of the disks to APFS. here is the result.

 

[Boyd01]

Seems like something is wrong with that disk or something strange is happening on your computer. I would want to figure that out before spending money on something else. I have three T7's and 3 of the older T3's, never saw anything that bad on any of them, not even close (even with the T3's on USB-A).

 

[HaykD]

Today the results were better - the drives were connected to iMac, but iMac was shut down. The results are from tests on iMac and MBP M1.



However, leaving the drives on a powered-on iMac (no work was being done) for an hour, I noticed the drives become extremely hot and the speed was slowed down.



After moving the drives to MBP M1, the speed was restored to around 200MB/s. And it was restored to around 200MB/s on iMac. So I guess this is a thermal issue? However, 200MB/s is not that much too...

 

[Boyd01]

Still looks too slow to me. The T7 does get pretty warm when there is a lot of access, but not very warm when nothing is happening. I would not say that mine ever get "extremely hot", but that could be subjective. Do you have other USB devices connected that could be causing this?

 

[HaykD]

Still looks too slow to me. The T7 does get pretty warm when there is a lot of access, but not very warm when nothing is happening. I would not say that mine ever get "extremely hot", but that could be subjective. Do you have other USB devices connected that could be causing this?

No, 2 SSDs connected with TB3.

 

[Boyd01]

The T7 is not TB3, it's USB-C.

 

[HaykD]

The T7 is not TB3, it's USB-C.

Yes I meant the ports.

 

[HaykD]

BTW, here is a possible option I may stick with - https://www.fantomdrives.com/extreme-thunderbolt-3-portable-external-ssd+capacity-2TB~SSD A WD nvme ssd inside, good speed of writing is claimed. Not sure yet though... Any input would be appreciated.