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stanleystf

macrumors regular
Original poster
Apr 24, 2022
200
36
I've recently bought a Crucial external SSD. The format is Exfat.

I've copied two large folders that contain videos onto it. On Mac, when I open folder A and play the videos in it, everything is fine. But when I open folder B, the ssd slows down and I can't play the videos in it.

I connected the drive to a windows machine, and there, it reads all the files from the two folders just fine.

Is there anything I can do? Why is it working okay on Windows and not Mac? I don't think the problem is "Exfat" format because I have other drives that are exfat and work fine on my macbook pro m1 2021.

Do you think I should change the format to APFS? Can I do that without erasing the data?
 

bradman83

macrumors 6502a
Oct 29, 2020
990
2,449
Buffalo, NY
What connection speed is the SSD rated at? 5 Gbps? 10 Gbps? 20?

The USB controllers in M1 and M2 Macs (including Pro/Max/Ultra variants) are fussy about connecting at full speed if the external SSD uses dual channel USB connections. They'll only connect using a single channel at half the speed.

Case and point, I have a SanDisk Extreme 1TB SSD which connects to an Intel Mac at the full 10 Gbps but will only connect to an M1 Pro MBP at 5 Gbps and there is notable lag in loading folders. If I connect the Mac to a Thunderbolt 3 dock and connect the drive to the dock it connects at full speed because it's using the dock's USB controller and not the controller in the Mac.

I can't say this for sure but I theorize part of the performance issue isn't just the drive connecting at half the speed but the fact that the drive's SSD controllers is expecting two channels to work with but the Mac is only allowing a single channel.

By contrast I have a second drive based on a Sabrent tool-free USB-C enclosure that uses single channel USB and it can connect at the full 10 Gbps.

You can check the connection speed using the System Report found under About this Mac and selecting "USB" from the sidebar list with the drive connected. If it shows "Limited to 5 Gbps" then you're not getting the full speed out of your drive. Unfortunately this is a problem Apple has acknowledged and claims could be fixed with a software update but has done nothing about. The only solution is to use a Thunderbolt 3 dock to bypass the controller or use a different drive.

It's also worth noting that no Macs support USB 3.2 speeds, nor do they support the x2 speed variants that allow 20 Gbps connections (which also require two channels). Unfortunately you have to be extremely diligent when shopping for an external SSD to use with an M-series Mac because most manufacturers don't advertise whether they use single channel or dual channel mode to achieve 10 Gbps.
 

stanleystf

macrumors regular
Original poster
Apr 24, 2022
200
36
What connection speed is the SSD rated at? 5 Gbps? 10 Gbps? 20?

The USB controllers in M1 and M2 Macs (including Pro/Max/Ultra variants) are fussy about connecting at full speed if the external SSD uses dual channel USB connections. They'll only connect using a single channel at half the speed.

Case and point, I have a SanDisk Extreme 1TB SSD which connects to an Intel Mac at the full 10 Gbps but will only connect to an M1 Pro MBP at 5 Gbps and there is notable lag in loading folders. If I connect the Mac to a Thunderbolt 3 dock and connect the drive to the dock it connects at full speed because it's using the dock's USB controller and not the controller in the Mac.

I can't say this for sure but I theorize part of the performance issue isn't just the drive connecting at half the speed but the fact that the drive's SSD controllers is expecting two channels to work with but the Mac is only allowing a single channel.

By contrast I have a second drive based on a Sabrent tool-free USB-C enclosure that uses single channel USB and it can connect at the full 10 Gbps.

You can check the connection speed using the System Report found under About this Mac and selecting "USB" from the sidebar list with the drive connected. If it shows "Limited to 5 Gbps" then you're not getting the full speed out of your drive. Unfortunately this is a problem Apple has acknowledged and claims could be fixed with a software update but has done nothing about. The only solution is to use a Thunderbolt 3 dock to bypass the controller or use a different drive.

It's also worth noting that no Macs support USB 3.2 speeds, nor do they support the x2 speed variants that allow 20 Gbps connections (which also require two channels). Unfortunately you have to be extremely diligent when shopping for an external SSD to use with an M-series Mac because most manufacturers don't advertise whether they use single channel or dual channel mode to achieve 10 Gbps.
Thank you for a helpful post!

According to this page, it's 10Gbps:


So, do you think the only solution is to use a dock/hub?

Do you think re-formating the drive to APFS might help?
 

bradman83

macrumors 6502a
Oct 29, 2020
990
2,449
Buffalo, NY
Thank you for a helpful post!

According to this page, it's 10Gbps:


So, do you think the only solution is to use a dock/hub?

Do you think re-formating the drive to APFS might help?
Check the System Report to see if it's connecting at 5 or 10 Gbps. If it's connecting at 5 then reformatting won't help. You would have to go the Thunderbolt dock route (note that it has to be a Thunderbolt dock since it has its own controllers for things like USB and networking - that's why they're so expensive compared to USB 3 hubs which do not include those components).
 
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stanleystf

macrumors regular
Original poster
Apr 24, 2022
200
36
Check the System Report to see if it's connecting at 5 or 10 Gbps. If it's connecting at 5 then reformatting won't help. You would have to go the Thunderbolt dock route (note that it has to be a Thunderbolt dock since it has its own controllers for things like USB and networking - that's why they're so expensive compared to USB 3 hubs which do not include those components).
That's what it says:

Screenshot 2023-01-15 at 7.11.17 PM copy.jpg
 

bradman83

macrumors 6502a
Oct 29, 2020
990
2,449
Buffalo, NY
The good news is that means it's not the drive itself that's the problem.

You can try reformatting the drive in APFS format. There are a number of reports that the file system drivers for ExFAT on Mac aren't that great, so you could potentially see a performance boost. The issue is that you would lose the data on the drive so you'd need to figure out a temporary storage solution.
 
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stanleystf

macrumors regular
Original poster
Apr 24, 2022
200
36
The good news is that means it's not the drive itself that's the problem.

You can try reformatting the drive in APFS format. There are a number of reports that the file system drivers for ExFAT on Mac aren't that great, so you could potentially see a performance boost. The issue is that you would lose the data on the drive so you'd need to figure out a temporary storage solution.
But the thing is, I have a 2tb Samsung SSD in exfat format. It's working fine on my Macbook.

And the Samsung SSD is 5Gbs!
 

FreakinEurekan

macrumors 603
Sep 8, 2011
5,719
2,758
If you're using a disk only on a Mac, then APFS is the better format to choose. But if the disk needs to be readable on either Mac or Windows, exFAT is the proper format - and I don't see any reason why that might happen. What I'd suggest, is on Windows - create a 3rd folder "C", and move half the videos from folder "B" into the "C" folder. Then test it on the Mac. If "B" and "C" perform differently (i.e. one is fast, the other isn't) it might be one of the videos in that folder. Continue moving half the videos from the slower folder until you narrow it down to which one.
 
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stanleystf

macrumors regular
Original poster
Apr 24, 2022
200
36
If you're using a disk only on a Mac, then APFS is the better format to choose. But if the disk needs to be readable on either Mac or Windows, exFAT is the proper format - and I don't see any reason why that might happen. What I'd suggest, is on Windows - create a 3rd folder "C", and move half the videos from folder "B" into the "C" folder. Then test it on the Mac. If "B" and "C" perform differently (i.e. one is fast, the other isn't) it might be one of the videos in that folder. Continue moving half the videos from the slower folder until you narrow it down to which one.
On Windows, the videos from both folders are played seamlessly. So I don't think that's the problem. On Mac, when I open folder B, I get that annoying spinning wheel for a few minutes! The SSD becomes very slow in folder B!

Apparently, this is an issue with Ventura!

 

Honza1

macrumors 6502a
Nov 30, 2013
933
433
US
Windows and Macs do have different handling of disk errors.
Check the disk in Disk Utility.app to see if there may be any minor issues with the records which Mac is poorly handling. Or simply delete the slow folder and copy again, that might be enough.
Or reformat the drive to APFS and copy again.
 
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FreakinEurekan

macrumors 603
Sep 8, 2011
5,719
2,758
Apparently, this is an issue with Ventura!
Apparently “What” is an issue with Ventura? It’s not disk speed - folder “A” works fine. So what’s different about Folder “B”? The files in it.

I’m not disputing that Ventura may be choking on something it shouldn’t, or that Windows isn’t having that problem. What I’m giving you, is steps to work around it. If you just want to complain, not actually fix it - well, I guess you’re in the right place 🤣 but if you want to improve the situation, follow those steps.
 
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Fishrrman

macrumors Penryn
Feb 20, 2009
28,500
12,632
What are you trying to DO with these videos on the exFAT drive?

Are you just trying to WATCH them?

If so, copy a video or two from "the problem folder" on the exFAT drive to the MacBook Pro.
Try playing the video from there.
Any better?
When done, just delete it.
 
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