Crucial X9 Pro Portable SSD Review: Micron 176L 3D NAND Delivers Record UFD Consistency

Crucial's flash-based storage lineup has had a distinctive focus on internal SSDs, with a range of options catering to both mainstream and power users. On the portable SSD front, the company's X6 and X8 Portable SSDs have been attractive budget options for the mainstream consumers. However, these drives use QLC and are not entirely suitable for power users (such as content creators) who require writing vast amounts of data as quickly as possible.

The company introduced two new products in the PSSD category in July 2023 - the USB 3.2 Gen 2 X9 Pro, and the USB 3.2 Gen 2x2 X10 Pro. These 1 GBps and 2 GBps-class drives come with a Type-C port and a Type-C to Type-C cable (Type-A adapter sold separately). The performance specifications of these two products indicate suitability for power users - for the first time, the company is quoting write speeds for their PSSDs in the marketing material.

Crucial sampled the 2TB version of the X9 Pro for review, and we put it through our rigorous direct-attached test suite. This review takes a detailed look at the performance and value proposition of the PSSD, with a particular focus on how it stacks up against the existing players in the segment.

Introduction and Product Impressions

Flash technology has seen rapid advancements in recent years (such as the development of 3D NAND and improvements in TLC reliability). These have been accompanied by the appearance of faster host interfaces for external devices. Together, they have contributed to bus-powered direct-attached storage devices growing in both storage capacity and speeds. The Type-C standard has also achieved widespread acceptance in the consumer market. Protocols such as USB 3.2 Gen 2x2 / USB4 and Thunderbolt riding on top of the Type-C connector have enabled the introduction of palm-sized flash-based storage devices capable of delivering 2GBps+ speeds. The 10 Gbps USB 3.2 Gen 2 interface has become ubiquitous in moder systems and has emerged as the sweet spot for mainstream users.

One of the primary challenges with high-speed storage devices is the thermal aspect. Bridge-based solutions with multiple protocol conversion chips tend to dissipate more power due to the additional components. High-performance portable SSDs in the past have had no option but to use them - first, with SATA bridges, and then with NVMe bridges. The introduction of native UFD controllers capable of hitting 10 Gbps and 20 Gbps from Phison and Silicon Motion has opened up yet another option in this category. The Crucial X6, equipped with the Phison U17, was reviewed in August 2021 and was one of the first retail products to surpass the SATA speeds barrier by hitting 800 MBps speeds without using a NVMe bridge. Around the same time, Silicon Motion's SM2320 powered the Kingston XS2000 to 20 Gbps speeds without a bridge in the middle.

Products based on Silicon Motion's SM2320 have gained a lot of consumer mindshare because they have typically been able to hit the interface speed limits for sequential accesses in both the 10 Gbps and 20 Gbps categories. However, consistency was an issue as the initial wave of products used Micron's 96L 3D TLC or BiCS 4 / BiCS 5 (up to 112L) 3D TLC NAND. The introduction of faster flash has since allowed portable SSDs (PSSDs) based on the native UFD controllers to hit higher speeds and maintain them even in direct-to-TLC scenarios.

The X9 Pro we are looking at in this review is a 38g 65mm x 50mm USB 3.2 Gen 2 PSSD made of anodized aluminum. It includes a lanyard hole (with the LED near the hole, rather than near the Type-C port) and a rubberized soft-touch base for protection against bumps. The sides are slightly recessed for better traction during handling. It is IP55 rated, and drop-proof up to 7.5'. The packaging is minimal - a short USB 3.2 Gen 2 Type-C to Type-C cable and a user guide in addition to the main unit.

The Silicon Motion SM2320 native controller and Micron's 176L 3D TLC NAND packages are seen in the board. Each package appears to have eight 1 Tbit dies.

CrystalDiskInfo provides a quick overview of the capabilities of the internal storage device. TRIM and NCQ are not seen in the features list, though we have seen those available in other PSSDs based on the Silicon Motion SM2320. Crucial indicated that TRIM support will be enabled in the next firmware update. We will see in the next section that native command queuing is active in the PSSD, and all S.M.A.R.T features such as temperature read outs worked well.

S.M.A.R.T Passthrough - CrystalDiskInfo
Crucial X9 Pro 2TBSDP G-DRIVE 2TBSamsung T7 Shield 2TBSDP PRO-G40 2TB [ASM2342]SDP G-DRIVE ArmorLock 2TB	SDP G-DRIVE 2TBSamsung T7 Shield 2TBSDP PRO-G40 2TB [ASM2342]SDP G-DRIVE ArmorLock 2TBCrucial X9 Pro 2TB

The table below presents a comparative view of the specifications of the different 2TB 1 GBps-class PSSDs presented in this review.

Prior to looking at the benchmark numbers, power consumption, and thermal solution effectiveness, a description of the testbed setup and evaluation methodology is provided.

Testbed Setup and Evaluation Methodology

Direct-attached storage devices (including thumb drives) are evaluated using the Quartz Canyon NUC (essentially, the Xeon / ECC version of the Ghost Canyon NUC) configured with 2x 16GB DDR4-2667 ECC SODIMMs and a PCIe 3.0 x4 NVMe SSD - the IM2P33E8 1TB from ADATA.

The most attractive aspect of the Quartz Canyon NUC is the presence of two PCIe slots (electrically, x16 and x4) for add-in cards. In the absence of a discrete GPU - for which there is no need in a DAS testbed - both slots are available. In fact, we also added a spare SanDisk Extreme PRO M.2 NVMe SSD to the CPU direct-attached M.2 22110 slot in the baseboard in order to avoid DMI bottlenecks when evaluating Thunderbolt 3 devices. This still allows for two add-in cards operating at x8 (x16 electrical) and x4 (x4 electrical). Since the Quartz Canyon NUC doesn't have a native USB 3.2 Gen 2x2 port, Silverstone's SST-ECU06 add-in card was installed in the x4 slot. All non-Thunderbolt devices are tested using the Type-C port enabled by the SST-ECU06.

The specifications of the testbed are summarized in the table below:

The testbed hardware is only one segment of the evaluation. Over the last few years, the typical direct-attached storage workloads for memory cards have also evolved. High bit-rate 4K videos at 60fps have become quite common, and 8K videos are starting to make an appearance. Game install sizes have also grown steadily even in portable game consoles, thanks to high resolution textures and artwork. Keeping these in mind, our evaluation scheme for portable SSDs and UFDs involves multiple workloads which are described in detail in the corresponding sections.

• Synthetic workloads using CrystalDiskMark and ATTO
• Real-world access traces using PCMark 10's storage benchmark
• Custom robocopy workloads reflective of typical DAS usage
• Sequential write stress test

In the next couple of sections, we have an overview of the performance of the two PNY PSSDs in these benchmarks. Prior to providing concluding remarks, we have some observations on the drives' power consumption numbers and thermal solution also.