USB 4 & USB 3.2 GEN 2x2

[Jonathan Cross]

The new 24" iMac has USB 4.  The SanDisk Extreme PRO® Portable SSD V2 has USB 3.2GEN 2x2.  Can the two be connected and the SSD work at or near its advertised speed of 2GB/s (which I assume is 16Gb/s)?

Jonathan

[kers]

In the Netherlands the Dutch Tax has an advertising slogan:

"We cannot make it easier than this" 

[Eric Myrvaagnes]

In the Netherlands the Dutch Tax has an advertising slogan:

"We cannot make it easier than this" 

That's a better answer than I could give.

[armand]

I thought the answer is self explanatory but alas, it's not.
It appears the m1 TB3/USB4 supports USB 3.1 2x1 (10 Gb/s) but not USB 3.1 2x2 (20 Gb/s), so the extreme pro speed would go wasted vs the regular extreme.

[Jonathan Cross]

Hi Armand. My question related to 3.2 gen 2x2, not 3.1.  Does it make a difference?

Jonathan

[armand]

Hi Armand. My question related to 3.2 gen 2x2, not 3.1.  Does it make a difference?

Jonathan

Sorry, that’s what I meant. Substitute 3.2 for 3.1. As it is the current m1 stuff doesn’t support the 20 Gbs, only 10 Gbs (for USB 3.2 that is, works to 40 Gbs for TB3/USB4).

[Jonathan Cross]

Thanks Armand. I am glad I asked the question as I am interested in a 24” iMac to replace a 9 year old machine and will want a fast external ssd to go with it.
Best wishes,
Jonathan

[mcbroomf]

This doesn't help with the USB I/O performance of the M1 chipped Macs but the SABRENT Rocket XTRM-Q external SSD has an auto switch from Thunderbolt to USB and the 2 ports seem to be on separate TB buses.  So a device like the Rocket should work very fast and will also have the advantage of being able to connect to non TB systems.
https://eshop.macsales.com/blog/68484-thunderbolt-on-the-m1-mac-mini/

I placed an order on Amazon for the 8TB version, due in June.  I don't have an M1 Mac but have TB3 on my main laptop and desktop but can connect this to any port on any other machine.  I hope it works.

[armand]

This doesn't help with the USB I/O performance of the M1 chipped Macs but the SABRENT Rocket XTRM-Q external SSD has an auto switch from Thunderbolt to USB and the 2 ports seem to be on separate TB buses.  So a device like the Rocket should work very fast and will also have the advantage of being able to connect to non TB systems.
https://eshop.macsales.com/blog/68484-thunderbolt-on-the-m1-mac-mini/

I placed an order on Amazon for the 8TB version, due in June.  I don't have an M1 Mac but have TB3 on my main laptop and desktop but can connect this to any port on any other machine.  I hope it works.

Let us know. I'm strongly thinking to switch but I need an external drive for capacity, at least 4TB. The Sabrent one seems good if you don't move large volumes at once, I think then the buffer fills and the speed goes down dramatically but I need to read more about it: https://www.thessdreview.com/hardware/portable-ssds/sabrent-rocket-xtrm-q-thunderbolt-3-nvme-8tb-external-ssd-review-speechless/

[armand]

I'm going through things and it appears the state of external storage for MacBooks/mini is not that much better than 2 years ago when I last looked. That is if you want to maximize the performance and you need higher capacity.

Few options at 4TB+ that are very speedy. I think that in order to avoid disappointment it's best to focus on ~1Gbs read/write performance (USB 3.2 2x1) for the newer m1 Macs. Few options with TB3 that have high capacity, the Sabrent mentioned above, some OWC stuff.
The Sabrent seems to get very hot (?longevity) and slows down/?dies if you copy more than the buffer at once, it's much cheaper per capacity than others for a reason. On the OWC side I think the OWC Express 4M2 looks the most interesting. Sabrent also makes a dual NVME enclosure on TB3. But the funny (or not) part is all cost as much or more than the laptop/mini.

[Jonathan Cross]

This is all interesting.  I am actively thinking of getting an M1 iMac, but not ordering yet as my Apple store has not got one to see.  I have a Macbook and use a Sandisk 550MB/s SSD for Time Machine.  It works so much faster than a spinning disc portable HD.  I also have another Sandisk 550MB/s for current photos and I am very pleased with it using it on both the PC and Mac with LR, and my wife has one for her data.

If I get an M1 iMac I will get one with 16GB memory and 1TB internal SSD.  Data will be held on a 2TB external SSD.  I would then want Time Machine to use an SSD for backing up both internal and external SSDs in one session.  This means I would probably use a 4TB SSD as neither internal nor external SSD will be full; I like to keep spare space.  Archiving of photos will probably continue on my existing spinning discs.  What I do with my PC is to backup alternately on external HDs. I am wondering if I need 2 SSDs for Time machine alternate backups on a new M1 iMac. Decisions, decisions, but it is good to know the USB 4 limitations on the M1 iMac.

Best wishes,

Jonathan

[armand]

This is all interesting.  I am actively thinking of getting an M1 iMac, but not ordering yet as my Apple store has not got one to see.  I have a Macbook and use a Sandisk 550MB/s SSD for Time Machine.  It works so much faster than a spinning disc portable HD.  I also have another Sandisk 550MB/s for current photos and I am very pleased with it using it on both the PC and Mac with LR, and my wife has one for her data.

If I get an M1 iMac I will get one with 16GB memory and 1TB internal SSD.  Data will be held on a 2TB external SSD.  I would then want Time Machine to use an SSD for backing up both internal and external SSDs in one session.  This means I would probably use a 4TB SSD as neither internal nor external SSD will be full; I like to keep spare space.  Archiving of photos will probably continue on my existing spinning discs.  What I do with my PC is to backup alternately on external HDs. I am wondering if I need 2 SSDs for Time machine alternate backups on a new M1 iMac. Decisions, decisions, but it is good to know the USB 4 limitations on the M1 iMac.

Best wishes,

Jonathan

I think they are more USB 3.2 limitations, if these drives would be USB4 they should have no issues. So it would be better to wait until they show up as USB4 or TB3/4.

Another thing that I discovered is that there are many people who got worse reading/writing speeds when they connect to M1 macs vs Intel Macs, or even to a hub first and then to M1 (which is weird). As in 20-30% less.


I'm strongly considering M1 stuff, even though I've been Windows all my life (with a little dabble in Linux). I'll likely start with a MacBook Air to replace my current laptop only, was hoping to use it a desktop replacement but I need bigger/faster external storage unless I'm willing to settle for 10 Gbs. 10 Gbs is not that terrible after all, all my PC data stuff is on SATA3 SSD so limited to 500+ Mbs, and it's almost fast enough.

[Jonathan Cross]

Another thing that I discovered is that there are many people who got worse reading/writing speeds when they connect to M1 macs vs Intel Macs, or even to a hub first and then to M1 (which is weird). As in 20-30% less.

If I have interpreted this correctly, it is probably correct.  I have seen somewhere that if you connect a hub to an M1 port, then the speed of that port is shared by all the inlets/outlets on the hub, so the speed of a port on the hub will drop.

Jonathan

[armand]

If I have interpreted this correctly, it is probably correct.  I have seen somewhere that if you connect a hub to an M1 port, then the speed of that port is shared by all the inlets/outlets on the hub, so the speed of a port on the hub will drop.

Jonathan

I forgot to add a "than".
What I saw in terms of speed was, from faster to slower: SSD to Intel Mac > SSD to hub > SSD to M1. It didn't make sense why connecting to a hub would be faster, but I've read that for some SSD the M1 doesn't recognize properly and uses 5 Gb/s instead of 10 Gb/s. The hub however is recognized properly at 10 Gb/s. It seems of this crap is specific drive dependent.

Likely the safest bet is to use a TB3 if you plan to stay on Mac only. If not, either USB4 (have yet to see much on market) or model specific real world validated that it can go to 10 Gb/s (real world speeds ~ 900-950 MB/s).

Some links:
https://forums.macrumors.com/threads/fastest-nvme-external-enclosure-with-m1.2272255/
https://forums.macrumors.com/threads/usb-on-m1-macs-isnt-actually-10gb-s-also-definitely-not-usb4.2269777/page-3?post=29331260#post-29331260

[Jonathan Cross]

Likely the safest bet is to use a TB3 if you plan to stay on Mac only. If not, either USB4 (have yet to see much on market) or model specific real world validated that it can go to 10 Gb/s (real world speeds ~ 900-950 MB/s).

Some links:
https://forums.macrumors.com/threads/fastest-nvme-external-enclosure-with-m1.2272255/
https://forums.macrumors.com/threads/usb-on-m1-macs-isnt-actually-10gb-s-also-definitely-not-usb4.2269777/page-3?post=29331260#post-29331260

I will wait until my Apple Store in the UK has one and then go talk to someone there about this.  If the questions are too hard then they can find out for me from HQ.  I am not going to buy any faster or bigger ssds until I have a definitive answer!
Thanks for the info.  If I find out any more I will post.
Jonathan