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Read and Write speeds to external SSD are sightly slower on M1 Pro vs Intel

S

syrcular

macrumors member
Original poster
May 17, 2013
67
65
Hi all

A few months ago, I tested read and write speeds with various external SSDs connected via USB-C, and noticed that performance was about 15-20% slower on my Mac mini M1, compared to my 2019 16-inch MacBook Pro Intel i9. Typically I would see read and write speeds of about 900-940MB/s R/W on the Intel MacBook Pro while I would get reduced speeds of about 500-700MB/s on the Mac mini M1.

I currently have a new MacBook Pro M1 Pro 14-inch with 8-core CPU and 16-core GPU, 16GB RAM, 512 SSD. Did the same test using Disk Speed Test (Blackmagic) and got similar results of reduced performance where I was averaging speeds of 700MB/s R/W when connected to the external SSD via USB-C.

Anyone know why I'm getting full performance on the external SSDs when connected to my Intel MacBook but when I connect the same SSD to M1 and M1 Pro based systems, I get reduced performance?
 
syrcular said:
Anyone know why I'm getting full performance on the external SSDs when connected to my Intel MacBook but when I connect the same SSD to M1 and M1 Pro based systems, I get reduced performance?
Click to expand...

I imagine it is down to differences in the USB controllers.

I would expect the Apple one to possibly be faster since I presume the controller is part of the SoC whereas the Intel controller should be in the northbridge/southbridge chipset which is external to the CPU, but it is what it is, apparently.
 
syrcular said:
Hi all

A few months ago, I tested read and write speeds with various external SSDs connected via USB-C, and noticed that performance was about 15-20% slower on my Mac mini M1, compared to my 2019 16-inch MacBook Pro Intel i9. Typically I would see read and write speeds of about 900-940MB/s R/W on the Intel MacBook Pro while I would get reduced speeds of about 500-700MB/s on the Mac mini M1.

I currently have a new MacBook Pro M1 Pro 14-inch with 8-core CPU and 16-core GPU, 16GB RAM, 512 SSD. Did the same test using Disk Speed Test (Blackmagic) and got similar results of reduced performance where I was averaging speeds of 700MB/s R/W when connected to the external SSD via USB-C.

Anyone know why I'm getting full performance on the external SSDs when connected to my Intel MacBook but when I connect the same SSD to M1 and M1 Pro based systems, I get reduced performance?
Click to expand...
There is a long thread on just this question at: https://forums.macrumors.com/thread...ually-10gb-s-also-definitely-not-usb4.2269777

The consensus seems to be that the Apple Silicon USB controllers are slower than the Intel ones.

It's quite disappointing that this hasn't been fixed in the new MBPs. The cynic in me would say that this is to "encourage" people to use Thunderbolt external SSDs instead of cheaper USB3.1/3.2 enclosures.
 
Fomalhaut said:
There is a long thread on just this question at: https://forums.macrumors.com/thread...ually-10gb-s-also-definitely-not-usb4.2269777

The consensus seems to be that the Apple Silicon USB controllers are slower than the Intel ones.

It's quite disappointing that this hasn't been fixed in the new MBPs. The cynic in me would say that this is to "encourage" people to use Thunderbolt external SSDs instead of cheaper USB3.1/3.2 enclosures.
Click to expand...

I would expect Apple uses the same USB controller across the M1/Pro/MAX family.

And I would not be surprised if that same controller shows up in the "M2" family, frankly.
 
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CWallace said:
I would expect Apple uses the same USB controller across the M1/Pro/MAX family.

And I would not be surprised if that same controller shows up in the "M2" family, frankly.
Click to expand...
Sadly, I think you are right. I suppose it makes the decision between USB and Thunderbolt drives easier. If you really need to high speeds, you go with Thunderbolt. If your needs are more modest you probably won't be that bothered by the 20% slower speeds on Apple Silicon.

In practice, I've found the Samsung T7 speeds to be "good enough" for my video editing. It will comfortable handle any 4K formats, even RAW, as long as the timelines are relatively simple. I would expect it to begin to struggle when trying to play back several video tracks simulaneously though, because it ceases to be a simple linear playback from a single file. When I get to more complex edits, I may need to consider a Thunderbolt external.
 
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I'm seeing the same thing on my T7 also when transferring files.

Intel deserves the knocks it gets these days, but their I/O chips have been top notch. AMD has had their share of USB issues and generally perform worse than Intel chipsets.
 
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Fomalhaut said:
Sadly, I think you are right. I suppose it makes the decision between USB and Thunderbolt drives easier. If you really need to high speeds, you go with Thunderbolt. If your needs are more modest you probably won't be that bothered by the 20% slower speeds on Apple Silicon.

In practice, I've found the Samsung T7 speeds to be "good enough" for my video editing. It will comfortable handle any 4K formats, even RAW, as long as the timelines are relatively simple. I would expect it to begin to struggle when trying to play back several video tracks simulaneously though, because it ceases to be a simple linear playback from a single file. When I get to more complex edits, I may need to consider a Thunderbolt external.
Click to expand...
This is all very good points to consider. I was worried this was a Thunderbolt and USB-C issue, but knowing that this issue is not prevalent in Thunderbolt based SSD drives, makes me feel a little better. I'm in a similar boat. Although I'm a bit upset that I'm not getting top speeds of my fast USB-C drives, which I recently purchased, it is good to know that I can get more appropriately fast read/write speeds with Thunderbolt 3 or 4. Which also makes my OWC Thunderbolt 4 Hub still relevant for future consideration. Right now I mainly edit compressed 4K files from cameras like the Sony A1 or A7sIII, and occasionally Canon R5 files which I think all should playback ok on the existing USB-C SSD drives that I have now. If my needs become more complex, like you mention, then I can look at a Thunderbolt 3 or 4 external SSD, which should give me better speeds well above 1000MB/s.
 
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