Crucial X6 4TB portable SSD review: A ton of on-the-go storage


The new Crucial X6 is an affordable external USB-C SSD designed for high capacity and maximum portability. The drive is well priced for those who need a significant amount of faster, more reliable storage than what you get with a portable hard drive, making it a contender for our list of best external SSDs. but its rated performance is nothing to write home about and it comes with minimal frills and extras.

Crucial’s original X6 used a DRAM-less SATA controller with a similar type of flash, but was limited to 540MB/s of sequential read throughput. The new model, tested at 4TB capacity, is rated for up to 800 Mbps. This makes it a good choice for on-the-go storage or if you want something relatively quick to back up your data. However, its performance is definitely limited. So while it can survive a drop from a height, you need to keep your performance expectations in check. Content creators might want to look at something like the Samsung T7 Shield instead.

This drive is lightweight and small in size, making it easy to throw in your laptop bag or backpack. It’s also built to survive drops and runs pretty cool. However, it doesn’t come with a Type-A cable, which might reduce its appeal.


Product 500 GB 1TB 2TB 4TB
Pricing $59.99 $79.99 $169.99 $359.99
Capacity (User / Raw) 500 GB / 512 GB 1000 GB / 1024 GB 2000 GB / 2048 GB 4000 GB / 4096 GB
Form factor
Interface / Protocol USB-C / USB Gen3 2×1 USB-C / USB Gen3 2×1 USB-C / USB Gen3 2×1 USB-C / USB 3.2 Gen 2×1
Included USB Type-C to Type-C Cable USB Type-C to Type-C Cable USB Type-C to Type-C Cable USB Type-C to Type-C Cable
Controller Phison U17 Phison U17 Phison U17 Phison U17
DRACHMA Nope Nope Nope Nope
Memory Micron 176L QLC (N48R) Micron 176L QLC (N48R) Micron 176L QLC (N48R) Micron 176L QLC (N48R)
Sequential reading 540Mbps 800Mbps 800Mbps 800Mbps
Sequential write N / A N / A N / A N / A
Shuffle Playback N / A N / A N / A N / A
Random write N / A N / A N / A N / A
Security N / A N / A N / A N / A
Power Bus Powered Bus Powered Bus Powered Bus Powered
Endurance Drop resistant (2m) Drop resistant (2m) Drop resistant (2m) Drop resistant (2m)
Stamina (TBW) N / A N / A N / A N / A
Dimensions 11 x 69 x 64 mm (LxWxH) 11 x 69 x 64 mm (LxWxH) 11 x 69 x 64 mm (LxWxH) 11 x 69 x 64 mm (LxWxH)
Article number CT500X6SSD9 CT1000X6SSD9 CT2000X6SSD9 CT4000X6SSD9
guarantee 3 years 3 years 3 years 3 years

The Crucial X6 is available in 500GB, 1TB, 2TB, and 4TB. The 500GB SKU is still limited to the original peak read throughput of 540MB/s; however, larger models are now rated up to 800 Mbps for sequential reads. The discs are drop-proof up to two meters, or about 6.5 feet. The reader is small and light in every incarnation, specified as less than 1.5 ounces and easy to fit in a pocket. Crucial backs this drive with a three-year warranty.

Price is best at 1TB or higher capacities, and that’s where you should be looking to buy a drive like this anyway. Although the cost per gigabyte may be lower, it is still reasonable compared to its competitors. It would be better if you bought it for a basic storage expansion; the Crucial X6 is not intended to be a premium product.

Software and accessories

(Image credit: Tom’s Hardware)

The Crucial X6 comes with a Type-C to Type-C cable, but you can use a Type-C to Type-A cable if you purchase one separately. Crucial’s free, downloadable Storage Executive software works with the X6, allowing you to get firmware updates, manage drive functions, and monitor drive health. Crucial’s Momentum Cache feature provides the ability to dedicate system memory (RAM) to serve as a disk cache, but we do not recommend this feature due to data integrity issues in the event of an unexpected disconnect or data loss. Powerful.

To look closer

The Crucial X6 comes in a relatively small rounded black case, but Crucial claims it can survive a two-meter drop. One side has a USB-C connector for connecting the included Type-C to Type-C cable, while the back lists basic drive information like its capacity and serial number. There’s nothing flashy here, but the reader’s small size and lightweight nature make it quite portable.

Internally we see EMI shielding, tape and thermal padding. The latter should allow the drive to stay relatively cool during prolonged use. Beneath it all is the PCB, which includes a DRAM-less controller and, for the 4TB SKU, two NAND packages on each side (for a total of four).

(Image credit: Tom’s Hardware)

A closer look at the controller lets us see various power circuits centered around the Phison PS6103 PMIC. The lack of a bridge chip tells us that this controller is an on-board hybrid design that handles both interface and flash.

The original Phison PS2251-17 controller was used for USB flash drives with USB 3.2 Gen 2×1 interface and Type A connector. It is often limited in speed and capacity when used for this application. Phison has more recently developed the U17 from this base, with the same interface but a Type-C connector. The controller is also capable of handling up to 4TB of flash memory and can reach higher speeds. The U17 is a native UFD controller in the same vein as Silicon Motion’s SM2320, which is used in the Kingston XS2000.

In this case we have a USB-C connector and speeds of up to 800Mbps – less than the 10Gbps and 1GBps U17 interface can handle – paired with QLC up to 4TB. This dual controller channels typically handles up to sixteen matrices, so this capability pushes the controller a bit. We previously reviewed the Inland Platinum External SSD, which uses the same QLC controller and flash, but is designed for higher speeds and only available at lower capacities.

(Image credit: Tom’s Hardware)

Flash modules are labeled NY165. These are 8TB (1TB) modules, for a total of 4TB. Each of the four modules has eight 1TB (128GB) QLC dies in an 8DP/ODP configuration. This is a new QLC flash, specifically Micron’s 176-layer QLC (N48R), based on the same architecture as its 176L TLC (B47R). We suspected this during testing, then later confirmed with Crucial, who said the updated player with the U17 launched with 96-layer QLC, but may now ship with the new flash.

This is a change from the floating-gate (FG) QLC that Micron has made in partnership with Intel at 64 and 96 layers. Micron previously used the 96L QLC on the original X6, paired with Silicon Motion’s DRAMless SM2259XT SATA controller with the 5 Gbps ASMedia ASM235CM bridge chip. This new QLC has appeared on some of Micron’s OEM drives and should be in the P3 and P3 Plus. We’ll cover the deeper technical aspects of Flash in the Flash review.

The SSD market is expected to see more 176-layer QLCs or equivalent from multiple manufacturers in the coming months. This is relevant because it suggests that QLC could finally grab a decent share of the market while still being good enough to replace TLC in many cases. It also means we’ll have bigger drives with a lower cost per gigabyte, especially as NAND prices continue to fall. Products like the 4TB X6 will become more mainstream, especially with newer UFD controllers, so use this review as a reference.

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