External SSD Actual Speed Capabilities Thunderbolt 4 Port

[PGB1]

Hi All!
After researching external drives for my MacBook Air M4 with Thunderbolt 4 ports, I saw many fine print notes on manufacturers' pages saying that the listed Read & Write speeds can't be achieved on Macs with Thunderbolt 4 ports. Reading general on line articles gave, like usual, conflicting information. Here are the questions for which I can't find a definitive answer:

A) For Time Machine, I'd like a reasonably fast drive in case I ever re-purpose it. Several drives advertise 1050 Mbps Read, 1000 Mbps Write with USB-C 3.2 Gen 2 interface. Some say Nvme. But, many say that Mac with Thunderbolt 4 won't achieve those speeds.

With a USB-C cable into the Mac's Thunderbolt 4 port, will this drive achieve 1050/1000 or will it fall back to a slower speed? Some sites say it will fall back as slow as 50 Mbps on a Mac with Thunderbolt 4.

B) For a drive to use as an external, general use drive; to achieve full Thunderbolt 4 speeds, am I correct to get the following:
Drive stated as Thunderbolt 4, 40 Gbps or higher
Cable stated as Thunderbolt 4
What speed can be expected? Is 40 Gbps maximum correct?

Thank You For Clearing Up Much Confusion! Your help is appreciated.
Paul

 

[Randy B. Singer]

- No Macintosh supports USB 3.2 (20Mbps).

- USB 3.1 is supported by some Macs. (10Gbps) (Sometimes confusingly referred to as USB 3.2 Gen 2.)

- Thunderbolt 4, Thunderbolt 3, and USB 4 all achieve a theoretical 40Gbps. They have other differences, but the speed that they support is the same.

- Any theoretical speed will be higher than the speed that you will actually see.

- To achieve close to the theoretical speed you are aiming for, your port, cable, and device all have to support that speed.

- USB-C is a port configuration, not a transmission protocol.
USB-3.1, USB-4, Thunderbolt 3, and Thunderbolt 4 all specify USB-C ports.
Note that that means that different USB-C ports and different USB-C cables do not necessarily offer the same performance.

- Not every USB-C port in any given single Macintosh model offers the same exact protocols. This is expecially true in the latest M4 Mac minis. Even if a given model is advertised as offering a certain protocol (e.g. USB-4) make sure that the port that you are connecting to supports the performance you are hoping to achieve.

- Just about every already assembled and ready to use external SSD will only support up to a theoretical 10Gbps when attached to a Macintosh. (e.g. the wildly popular Samsung T7.)

- This external SSD is rated for a theoretical 40Gbps. I haven't tested it myself. I've heard from one user who purchased it and tried it and he said that it was stunningly fast. Note that this external SSD also offers a cooling fan, which IMHO is vital to prevent thermal throttling:

1TB External SSD, USB4 40Gbps Portable SSD 1TB with Cooling Fan, Up to 3700MB/s, External Solid State Drives Compatible with iPhone 15/16 Pro, Tablets, MacBook,iPad, iMac, etc(FP110)
$160
https://www.amazon.com/External-Por...110/dp/B0DTHRTVHY/ref=cm_cr_arp_d_product_top

 

[pm-r]

Thank You For Clearing Up Much Confusion! Your help is appreciated.
Paul

Excellent questions. Thanks, Paul, I must admit, I have been wondering similar questions, and it's an amazingly confusing amount of seemingly misleading information out there in the computer world of sales and marketing.

And why do they bother spewing the information about theoretical speed? Why even bother when they can't even be reached in most cases?

I can certainly live without using the fastest drive available, but I would definitely like to have a reasonably fast R/W hard drive that I can afford that is also, and probably more important, completely reliable.




- Patrick
=======

 

[PGB1]

Thank You Randy & Patrick for taking time to reply.

Thanks Randy for your excellent explanation. Finally an honest and understandable explanation! Selecting s drive will be much easier now. Thanks, too, for the link to the Fikwot drive.

Thank You Patrick for confirming that I'm not the only person confused by all the marketing stuff. I'm going to go purchase based on two things that you mentioned- "...reasonably fast" and "...completely reliable".

"Reliable" leaves out the 16 TB, 500 Mbps Read for 11.35 USD. I wasn't really considering it. 16TB for $11.35? Here's a link: Robot or human? (Don't know why the link says "Robot or Human". It';s Walmart.)

Thanks Again!
Paul

 

[Randy B. Singer]

16TB for $11.35?

There are several no-name Chinese SSD's that are complete scams. Fortunately they tip you off right away by having prices that are too good to be true.

When you get them they actually seem to be what they advertise. But when disassembled they contain a cheap SD card that has a tiny capacity that has been programmed to report that it has a huge amount of storage space.

 

[MacBiter]

There are several no-name Chinese SSD's that are complete scams. Fortunately they tip you off right away by having prices that are too good to be true.

When you get them they actually seem to be what they advertise. But when disassembled they contain a cheap SD card that has a tiny capacity that has been programmed to report that it has a huge amount of storage space.

Yes, I've been warning about these for absolute ages. Gullible people buy them and say quite happily that they can write TBs of data to them so they must be ok. However, if they were to examine the data they would find that only the most recent few GBs (or whatever the real capacity is) is actually there - all the earlier stuff was just continuously overwritten.

 

[Randy B. Singer]

...Thanks, too, for the link to the Fikwot drive...

I"ve gotta say, that may be the most regrettable name for a product ever....

 

[MacBiter]

I"ve gotta say, that may be the most regrettable name for a product ever....

I dunno - the i could have been a u and the o could have been an i .