Connecting a 4TB external SSD via thunderbolt - will I see any speed benefit with the Crucial X10 over the X9?

GDB1976 wrote:

Oops, didn’t have my head on straight. At 10 Gbps, the USB 3.2 gen2 / thunderbolt isn’t going to be the limiting factor at all. Thanks for helping get my brain working!

USB 3.1 Gen 2 will be a limiting factor for the Crucial X10 Pro. 10 Gb/s (gigabits per second) is the same as 1250 MB/s (megabytes per second), and Crucial claims that the X10 Pro has speeds of up to 2100 MB/s.

As far as I know,

• There are no Macs that implement USB 3.2 Gen 2x2 ("up to 20 Gbps").
• Apple doesn't refer to ports on current Macs as USB 3.2 ports – only as USB 3, USB 3.1, or USB4 ones.
• If someone says that a port is "USB 3.2 Gen 2" without specifying the number of lanes, it very often means that they are referring to USB 3.2 Gen 2x1 ("up to 10 Gbps") – basically another name for USB 3.1 Gen 2.

Note also that neither of these SSDs connect over Thunderbolt. Neither understands Thunderbolt; both connect using USB protocol.

There are external NVMes that connect via Thunderbolt 3. These can run much faster than SSDs connected via USB 3.1 Gen 2 – although you might not notice the difference unless you routinely did large file transfers. The Thunderbolt enclosures tend to make these SSDs more expensive, and the speeds at which these SSDs operate often cause them to throw off a fair amount of waste heat.

That Crucial X10 Pro uses USB 3.2 Gen 2 2x2 (20Gbps) and Apple has not implemented the 2x2 protocol yet. Thus, on paper this drive sounds good, but is the wrong drive and uses a special USB cable that may not interoperate with ports on the Mac.

Plan B is to look at the OWC 1M2 external drive enclosure which is a proper USB4 unit and provides SSD speeds up to 3151 MB/s. You could use OWC's enclosure with their choice of NVME M.2 drive, or just purchase the enclosure and add your separately purchased NVME M.2 drive. If the latter, consult with OWC on which brands and models they have tested so you get it right the first time. You would connect this drive to an available Thunderbolt 3 port on the iMac.

VikingOSX wrote:

That Crucial X10 Pro uses USB 3.2 Gen 2 2x2 (20Gbps) and Apple has not implemented the 2x2 protocol yet. Thus, on paper this drive sounds good, but is the wrong drive and uses a special USB cable that may not interoperate with ports on the Mac.

I doubt if a USB-C cable rated for USB 3.2 Gen 2x2 will have trouble interoperating with USB-C ports on Macs in USB 3.1 Gen 2 (a.k.a. USB 3.2 Gen 2x1) mode.

You'll get the lower speed, of course, but I'd be very surprised if the X10 Pro and the Mac failed to communicate with each other.

Plan B is to look at the OWC 1M2 external drive enclosure which is a proper USB4 unit and provides SSD speeds up to 3151 MB/s. You could use OWC's enclosure with their choice of NVME M.2 drive, or just purchase the enclosure and add your separately purchased NVME M.2 drive. If the latter, consult with OWC on which brands and models they have tested so you get it right the first time. You would connect this drive to an available Thunderbolt 3 port on the iMac.

This is the first USB4 40 Gbps peripheral that I've seen from anyone.

I am not familiar with the Crucial external pre-built SSD options, but they can be very deceiving. I know I was assisting another user on this forum when they found out their Crucial pre-built external SSD was a very poor performing SSD because under some conditions like writing lots of data in a short period of time can cause the SSD performance to tank. I believe they mentioned that particular external SSD was using the BX series SSD technology which I know from the 2.5" bare SSD is a terrible SSD that should be avoided. I have no idea how to tell the pre-built external SSDs apart, but I have seen mixed reviews on them....not that reviews can be trusted these days since the SSD manufacturers are modifying the product components without any model number change. My guess is the faster SSD would be the one to use even if your system is unable to maximize its potential, but very hard to say.

Yes, they are both USB 3.2 Gen 2, but the X10 Pro is a 2000 MB/s device and the X9 Pro is the same performance as the X8 at 1050 MB/s.

Two things . . . why do you need those speeds and do you realise how simple it is to create your own SSD?

You have to buy an SSD plus an enclosure and assembling it is as quick and easy as changing the batteries in a TV remote control.

More conversations about plugging a USB 3.2 Gen 2 2x2 cable into Thunderbolt 3. Backwards compatible at 10 Gbps.