Sabrent XTRM-Q SSD review: 8TB of pocket-sized Thunderbolt 3/USB storage

Realize top performance across platforms using this small, capacious, 10Gbps drive.

Credit: Sabrent

Sabrent’s pocket-sized Rocket XTRM-Q external SSD offers the kick in the pants transfer speed (up to 10Gbps) provided by the Mac’s Thunderbolt 3, while adding the ability to operate via USB on computers that lack it. It is also available in a hitherto unheard of capacity of 8TB. Nice. Very nice. 

Design and specs

The Rocket XTRM-Q (extreme/QLC) is a small, handsome, dark-slate colored monolith measuring approximately 4 x 1.75 x 0.5 inches. It weighs around 5 ounces and there is a Type-C port on the business end.

Note that many companies (including Sabrent) advertise drives as USB-C and leave it at that. USB-C indicates USB connectivity and a Type-C port, but tells you nothing about performance. It might be SuperSpeed USB 5Gbps, it might be SuperSpeed USB 10Gbps or SuperSpeed USB 20Gbps. As noted, the XTRM-Q is SuperSpeed USB 10Gbps, née USB 3.x Gen 2, though you can only infer this from the Sabrent website’s mention of 900MBps transfers. Sigh.

You can purchase the Rocket XTRM-Q in 500GB ($170), 1TB ($220), 2TB ($360), 4TB ($830), and 8TB ($1,600) flavors. Yes, the 4TB and 8TB are pricey, but the price per gigabyte is actually lower than the 1TB model’s. You can of course get 4TB or 8TB of external storage for far less money, but not with the speed and convenience of a portable NVMe SSD.

The SSD inside the XTRM-Q is Sabrent’s own Rocket Q NVMe, which employs QLC (Quad-Level Cell/4-bit) NAND and a Phison controller. The warranty is for 5 years and Sabrent includes both Thunderbolt 3 and Type-A to Type-C cables. The former are a rather pricey item, so good on Sabrent. 


I tested the 8TB XTRM-Q via both Thunderbolt 3 and SuperSpeed USB 10Gbps. According to Sabrent, the 8TB model treats 25 percent (which works out to 2.5TB) of the QLC NAND on board as SLC cache, so there was no chance it would slow down during long writes. Though as free space declines, so does the amount of NAND allocated as cache.

Blackmagicdesign’s Disk Speed rating of the XTRM-Q’s sustained read and write performance, is not the fastest we’ve seen, but still nice.

disk speed xtrm q IDG

Though hardly the fastest external NVMe SSD we’ve tested, the XTRM-Q is the only one that also supports USB. And almost 2GBps is nothing to sneeze at.

CrystalDiskMark 6 also sees the XTRM-Q as quite fast, if not as fast as the Thunderbolt-only Fledging Shell. On the other hand, as you’ll see in a chart or two, the 1TB Shell slowed down drastically on the 450GB write. 

sabrent xtrm q cdm 6 IDG

The XTRM-Q was a good performer via both Thunderbolt 3 and USB 10Gbps, if not as fast in every test as its competitors. Longer bars are better. 

In our real world 48GB transfer tests, the XTRM-Q proved a decent Thunderbolt 3 performer, and a very good performer via USB 10Gbps.The Fledging Shell is Thunderbolt 3-only and the Samsung T7 is USB-only (10Gbps).

sabrent xtrm q 48gb IDG

As you can see, the XTRM-Q wasn’t the fastest drive among the four, however, it’s also the only one that can be used with both Thunderbolt 3 and USB. Shorter bars are better. 

The 450GB write test shown below is testament to what having 2.5TB of NAND cache will do for you. The amount of cache will shrink as the drive starts to fill up, and the 1TB and 500GB versions of the XTRM-Q will likely slow down before this test is finished due to having less than 450GB of cache. We did not have those capacities to test. 

sabrent xtrm q 450gb write IDG

This test highlights not only the XTRM-Q 8TB’s excellent sustained transfer abilities, but the advantage of Thunderbolt 3 over USB 10Gbps. Note that the 500GB and 1TB versions will post slower times due to less cache.

All in all, you’ll like the 8TB XTRM-Q’s performance. USB drives cross platforms, but so far this is the only external USB SSD we’ve tested that also offers speed of Thunderbolt 3. No compromises is a good thing. 

Testing is performed on Windows 10 64-bit running on a Core i7-5820K/Asus X99 Deluxe system with four 16GB Kingston 2666MHz DDR4 modules, a Zotac (Nvidia) GT 710 1GB x2 PCIe graphics card, and an Asmedia ASM2142 USB 3.1 Gen 2 (10Gbps) card. Also on board are a Gigabyte GC-Alpine Thunderbolt 3 card and Softperfect’s Ramdisk 3.4.6, which is used for the 48GB read and write tests. BlackMagic’s Disk Speed testing was performed on a similarly configured machine.

All testing was done with the drive formatted to NTFS (Windows) and HFS+ (Mac) to achieve best-case results. To cross platforms, you’ll need to either format the drive to exFAT (with slower small file writes), or employ additional file system drivers. We did not enable write caching for the drive as recommended by Sabrent. You can squeeze extra performance out of the XTRM-Q by doing this.

Bottom line

If you want the performance of Thunderbolt 3, but need to retain compatibility with USB-only computers, then the XTRM-Q is what you want. 8TB that fits in a shirt pocket ain’t half-bad either, even if it means removing a substantial number of Benjamins from your wallet. 

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Jon L. Jacobi
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