If you consider the speed, capacity, the Thunderbolt 3 + USB compatibility, the Rocket XTRM-Q 4TB is an excellent choice


  • TB3 and USB compatibility
  • High capacity
  • Excellent cost per GB
  • 5-years warranty


  • No encryption hardware
  • Not waterproof
  • Long warranty requires registration

Rating + Price

  • Rating: 9.3/10
  • Price: ~$699.99
  • Available on Amazon

Holding a Sabrent Rocket XTRM-Q 4TB in my hand

The Sabrent Rocket XTRM-Q 4TB is a high-performance external SSD drive compatible with both Thunderbolt 3 and USB protocols. I start with this because many users are shocked to learn that many Thunderbolt external hard drives are not compatible with the USB protocol, despite connecting via a USB-C cable.

That’s because people assume that having a USB-C physical connector makes a device USB-compatible. That’s unfortunately not the case. The Thunderbolt + USB ( up to USB 3.2) compatibility means that the Rocket XTRM-Q can work with any USB device or platform, including older computers and mobile devices.

This drive is powered by the USB cable only, and there’s no need for any additional power sources: that’s super convenient because it’s one less power brick to carry during travel.

Showing the aluminum chassis and USB-C port of the Sabrent Rocket XTRM-Q 4TB
The Sabrent Rocket XTRM-Q 4TB has gummy pads on the underbelly

The chassis is made of aluminum and seems highly sturdy. I’m not going to try breaking it, but it seems very unlikely that physical damage would affect the SSD drive inside (also from Sabrent) in case of a drop, even from a couple of stories high.

Sabrent also has a silicone cover called Shockproof Protector that provides even more protection if you want to take no chances at all. In my opinion, the soft shell avoids possible hard contact (in your backpack) with other surfaces, such as your expensive unibody aluminum laptop.

The shockproof protector for Sabrent SSD drive enclosures

The aluminum acts as a heat dissipator which is why products like these often use this material. The SSD can get hot during high workload, perhaps in the 60C/140F, depending on your ambient temperature. In any case, it’s hot enough that you would not want to touch it for extended periods.

I could reach these types of temperatures during heavy benchmarking, such as the PCMark 10 benchmark that lasts 45-90mn. That’s not an unrealistic scenario for people who do video editing or offline 3D rendering.

Huge dynamic cache

One of the most significant performance advantages of the Rocket XTRM-Q 4TB shows up in benchmarks: it automatically allocates 25% of the available drive capacity to the secondary write-cache layer, up to 1TB for this 4TB model. That’s huge.

When you copy a large file, the write speed would drop drastically if your file exceeds the cache size. The larger the cache is, and the less likely performance will decrease.

It’s important to understand that this drive utilizes QLC cells, which are the most efficient for SSD storage costs, although it is not the fastest. But there are excellent mitigation strategies.

Sabrent has integrated 8GB of DRAM as the first cache layer in the 4TB model to receive data as fast as possible from the PC. Then, 25% of the available QLC storage capacity cells are used in TLC mode, so SSD writes are faster. Finally, the TLC temporary storage will be moved in the background to QLC cells for final storage.

TLC is better for write-intensive workloads, so it’s very appropriate to use it in a cache layer. On the other hand, QLC is excellent for storage capacity and read-intensive tasks, so Sabrent effectively uses an efficient and balanced approach.

The only downside to this is that, as you fill the drive up, the 25% caching size also reduces because it is proportional to the remaining available storage. You will be hard-pressed to find a better alternative, but this is something to keep in mind if you plan to use the drive at near-capacity.

Performance: as fast as Thunderbolt can go

Our test unit is a Sabrent Rocket XTRM-Q 4TB, and that’s important because some performance aspects tend to be better on larger SSD drives, such as the Random 4K IOPS.

In a synthetic benchmark like CrystaldiskMark, the drive gets excellent sequential read and write performance (for an external drive) with 2967.79 MB/s and 982.73MB/s.

Remember that when connected via USB protocol, the performance will become limited by the connection and reach a ceiling near 1000 MB/s.

In the PCMark 10 full drive system drive benchmark, this model delivers 129.6 MB/s and an average access time of 206 μs. These numbers are well within the competitive landscape for these external devices as connectivity is the primary limiting factor here (not the drive), even with Thunderbolt 3 or 4.

In the real world, the performance is exactly what we expect from a drive like this. If you own an older computer with a rotational hard drive, you might even experience huge gains by booting on an external SSD such as this one. I’ve heard of many Mac users who have done it because Mac OS makes it super easy to boot on an external drive. 


The packaging of the Sabrent Rocket XTRM-Q 4TB

The Sabrent Rocket XTRM-Q series is outstanding, and the multi-TB capacity is awesome. Although our test unit is 4TB, you can now find an incredible 16TB model based on similar technology. If you consider the speed, capacity, the Thunderbolt 3 + USB compatibility, the Rocket XTRM-Q 4TB is an excellent choice for a high-capacity SSD. 

If you need something even more compact, the Samsung T7 2TB or the Sandisk 2TB Extreme Portable SSD could fit the bill, but they max out at 2TB and 1000MBps: that’s many times lower than the Rocket XTRM-Q maximum capacity and speed.

Hardware encryption and water resistance aren’t featured in this product, so there’s room for the competition to distinguish itself. These are legitimate use cases that might be more specialized than this Sabrent SSD offers.

The price per GB is highly competitive as well: with a street price of 699.99, this 4TB version yields a $0.175 per GB, which makes it challenging for Samsung or Sandisk to beat.

Based on my time with this storage device, I highly recommend this product and encourage buyers to register the product with Sabrent to extend the default 1-year warranty to 2 or 5 years.

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