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USB 3.2 Gen 2x2 on Thunderbolt 4

I have a MacBook Pro M1 model 2021 with three Thunderbolt 4 slots.

I am considering to buy a SanDisk SDSSDE81-2T00-G25 Extreme PRO portable NVMe SSD.

On the Internet I read the following warning:


This drive is capable of 2000mb/s, but your computer must support dual-lane USB 3.2 Gen 2X2, essentially using both lanes of USB-C connectors to deliver speeds up to 20Gbps (or 2.5GB/s). As of this date, no Mac products support the new USB 3.2 Gen 2x2 standard. They only support USB 3.2 gen 2, which is one lane at 10Gbps (or 1.25GB/s). So if you have an Apple/Mac machine, this will not work at its fullest speed. 


My question: is the latest model with Thunderbolt 4 compatible with the new USB 3.2 Gen 2x2 standard?

I cannot find any information about this.

MacBook Pro (2020 and later)

Posted on Nov 17, 2021 2:26 PM

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Question marked as Top-ranking reply

Posted on Nov 18, 2021 1:02 AM

Hi Hans,

Yes, support for the 2x2 standard is optional for OEMs. In this case the M1does not support it. I have a brand new MBP 16 inch M1 Max. The ports on the M1 are either Thunderbolt 4 / USB 4 @ 40Gbps or USB 3.2 gen2 @ 10Gbps… no in between



21 replies

Feb 23, 2022 9:26 AM in response to Kuttoh

It's VERY true that Thunderbolt 3 and Thunderbolt 4 (T3/T4) NVMe enclosures offer higher speeds. Theoretically, one day one may provide 40gbs. I edit videos and have never found one. The fastest EXTERNAL one I've ever found reaches 2700 to 2800mbs @27-28gbs over T3/T4 cables. Some T3 enclosures limit NVMe speeds to1600mbs. Always read credible expert reviews with actual SSD and enclosure speed tests. Consumer reviews showing low speeds may be due to ignorance of own capability issues.


SLC CACHE SIZE IS IMPORTANT IF YOU WORK WITH LARGE FILES

If you use large files, find BOTH an enclosure and an NVME that are EACH capable of high speeds AND ALSO ensure the NVMe either has a large SLC cache-- or at least know how much the NVMe drops speed after an SLC cache is full.


Even if an NVMe/enclosure combo can reach 2800mbs, after the SLC cache is full they can drop as low as 1100mbs, 700mbs, some even BELOW SATA III speeds. For example, if a 2800mbs capable enclosure houses a 5000mbs* capable NVMe and that NVMe only has a 20GB SLC cache, it will transfer/write ONLY the first 20GB of a larger file or folder at 2800mbs. After that, the speed can drop a LOT! l


I recommend a Trebleet enclosure. Learn more about SLC cache drops with real-world tests of popular SSDs in this video: https://youtu.be/W_uFdOIOb9I


*5000mbs is a speed only reached by top NVMe 4 SSDs in an internal NVMe motherboard slot. So far, such speeds are not available with an external drive.

Feb 4, 2022 3:16 AM in response to daddio-merts75

Sure!


To talk about the enclosure, I just bought this:

https://a.aliexpress.com/_9ibwkd

Didn't receive it yet, but it supports Thunderbolt 3 which means it will use it's whole bandwidth up to 40Gbps. I've chosen it because of an inbuilt fan that makes an NVMe SSD cooler which means it will last longer and you hopefully will never see any throttling.

There are also a lot of other devices made by Orico (you should choose one of a few that supports TB3 or USB4) and a few other brands, but none of it has a fan as I found out.


About the SSD, you can choose almost any NVMe SSD as long as:

  1. it is supported by your enclosure by dimensions, and the key (usually M-key). Sometimes enclosure manufacturers note that their devices are not compatible with some NVMe SSD's even if it has the right size and a key. It doesn't mean it wont work at all, but it can be pretty slow or get hot faster than it is supposed to. For example, my enclosure is not recommended to be used with Samsung 970 EVO PLUS. So I bought an expensive Samsung 980 PRO which will not limit my enclosure by any means (it has 7000 MBps speed or so) and is 100% compatible.
  2. It's speed is the same or faster than the speed of your enclosure (just to be sure that you are not limiting your cases capabilities with it).


Feel free to ask if you need some more info!

Apr 29, 2022 12:10 AM in response to Sonicray

Hi @Sonicray, I am not a pro on this subject. Please advise:

  1. If I go for a USB- 3.2 Gen2 x2 enclosure and couple it with M.2 Nvme 4Pcie and use on a iPAd Pro 2021 - I understand from the discussion here, I will be getting at least 1000 mbps speed. Is this setup ideal for video editing on the iPad Pro?
  2. Second option: If I buy a Thunderbolt 3 enclosure with the same SSD - I assume the transfer speed will be at least approximately equal to that of the drive's capability-maybe 3000 mbps if the drive supports around 3500 mbps as mentioned on their manual. My question is, if I use this custom SSD with thunderbolt enclosure on one of my PCs that support one of the USB-3, will the PC detect the drive or do I need to buy an enclosure that support both thunderbolt and USB-3? I am asking this because I was thinking all this while that thuderbolt standard by itself will support USB-C as well, I may be incorrect.
  3. After looking at the SLC-Cache discussions - what is your opinion on the "Kingston XS2000 2TB High Performance Portable SSD with USB C Pocket Sized USB 3.2 Gen 2x2 External Solid State Drive Up to 2000MB/s SXS2000/2000G" - will this work decently on my iPad Pro for video editing and photo editing?



Thanks in advance


Feb 23, 2022 9:19 AM in response to daddio-merts75

Daddio-Merts75,


If you want the most consistently fast external NVMe speeds even for large files, I HIGHLY recommend the Sabrent Rocket NVMe 4.0 Gen4 PCIe M.2 Extreme Performance SSD in a Trebleet Thunderbolt 3 enclosure.


You can even find a versatile Trebleet Thunderbolt 3 enclosure that also works with USB 3.2 Gen 2 if you might tranfer files to computer non-Thundebolt capable computer.


[Link Edited by Moderator]

Feb 24, 2022 1:52 AM in response to SonofWayne

I should probably add my 2 cents again…

the external enclosure for a USB 3.2 gen2 @ 10Gbps go for about ~$50 while the Thunderbolt 4 / USB 4 external enclosure go for about ~$200 (so, ask yourself if you really need that theoretical ~40Gbps.) So, it might be best to spend the money on a good SSD… As for the “Sabrent Rocket SSD” I would read the reviews first before buying, there is a large plethora of unhappy customers that have had their SSDs fail very quickly (myself included and I stay away from anything Sabrent) their QC/QA is not that great… I would buy from well trusted companies such as Samsung, Micron, Kingston, Sandisk…etc.


Orico’s external enclosures are a bag of mix feelings… sometimes they are fantastic and other times they fall short somewhere (98% of the time , it is the cheap, short cables.) However, their CS has never let me down and they do stand by their warranty (most of their latest enclosures have a lifetime warranty too)

Mar 1, 2022 6:19 AM in response to SonofWayne

Absolutely. None of TB3 or USB4 enclosures really reach maximum theoretical speeds.

Got mine a few weeks ago and it also shows 2300 MBps write and 2400 MBps read.


My initial message says: "In this case you should have all 40Gbps available" which is not 100% correct.

"UP TO 40 Gbps" might have been a better answer.


What I wanted to say is that maximum speeds of fast NVMe SSDs are reachable with TB3 or USB4 enclosures paired with compatible PCs or MACs, so people could understand why their disks sometimes doesn't reach designated numbers.

Mar 1, 2022 6:28 AM in response to SonofWayne

In my scenario, I was really worrying about temps, that's why I bought a fan-cooled enclosure.

I'm pretty sure that not much people will face overheating issues as in normal life usage you rarely transfer terabytes of data back and forth. So fan is not a must-have option.

But if you do, you will be happy with the fan, as I never seen temps higher than 50C, which is super low for such usage.

Mar 30, 2022 6:59 PM in response to Sonicray

Sonicray, just a few years ago I would agree with you about Sabrent in the same way that 15 years ago I wouldn’t buy from Logitech. Yet just as Logitech creates some amazing peripherals and some that aren’t so great, Sabrent has some amazing NVMe SSDs and all-in-one SSDs with enclosures now. Please note that I’m NOT recommending all Sabrent Rocket SSDs. I specifically rec the Sabrent Rocket NVMe 4.0 Gen4 PCIe M.2 Extreme Performance SSD. The reviews are great everywhere I’ve looked, Max Tech’s YouTube channel — which specializes in testing Macs and peripherals for Macs recs it, it has a 5-year warranty, and a massive SLC cache.

USB 3.2 Gen 2x2 on Thunderbolt 4

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