Sabrent Rocket XTRM-Q USB / Thunderbolt 3 Dual Mode External SSD Review: Yin and Yang

2020-12-16

The external storage market has shown renewed vigor in recent years, thanks in part to growth fueled by bus-powered flash-based storage solutions. The introduction of 3D NAND, coupled with the  has brought down the cost of these drives to the point where even a reasonably spacious external SSD can be had for an equally reasonable price. And though this means that NAND manufacturers like Western Digital, Samsung, and Crucial/Micron have an inherent advantage in terms of vertical integration, the availability of cheap flash in the open market has also enabled other vendors to come up with innovative solutions. Xeon Platinum 8156

Today, we're looking at a unique product in the external SSD market – the Sabrent Rocket XTRM-Q. A true dual-mode Thunderbolt 3/USB drive, the Rocket XTRM-Q can be natively used with both Thunderbolt 3 and USB hosts. This means that it can deliver speeds over 2GBps on a Thunderbolt 3 connection, or fall back to USB mode and still deliver 1GBps or more with a USB 3.2 Gen 2 connection. Compared to most external SSDs on the market, which are virtually always USB-only or Thunderbolt-only, this allows Sabrent's drive to offer USB-style universal compatibility while still making the most of the host it's connected to, using USB when it's available, or upgrading to Thunderbolt as appropriate to let the drive run as fast as it can.

Meanwhile, not unlike their , Sabrent is also at the leading-edge of storage capacity with the Rocket XTRM-Q, offering versions of the drive with up to 8TB of storage. Overall, the Rocket XTRM-Q is available in capacities ranging from 500GB up to 8TB, with Sabrent using QLC NAND across the family to hit their price and capacity goals.

For this review we're looking at two of the mid-tier Rocket XTRM-Q models – the 2TB and 4TB models – in order to size up the performance of the drives and see how they stack up against the other products in the market.

Introduction and Platform Analysis

External bus-powered storage devices have grown both in storage capacity as well as speeds over the last decade. Thanks to rapid advancements in flash technology (including the advent of 3D NAND and NVMe) as well as faster host interfaces (such as Thunderbolt 3 and USB 3.2 Gen 2x2), we now have palm-sized flash-based storage devices capable of delivering 2GBps+ speeds. Depending on the performance profile and the components used, these flash drives fall into one of six categories:

    Almost all external SSDs currently in the market can slot into one of the above categories. However, the Sabrent XTRM-Q we are looking at today is unique in falling into two categories in the above list. It is both a Thunderbolt 3 SSD and a USB 3.2 Gen 2 SSD.

     

    The XTRM-Q uses the Intel JHL7440 (Titan Ridge) Thunderbolt 3 controller to interface with the host system. Similar to the JHL6xxx Alpine Ridge host controllers, Titan Ridge also has a built-in xHCI controller that enables it to act as a USB 3.2 Gen 2 host. When used in a device configuration (i.e, in docks or peripherals), Titan Ridge has an extra feature not available in Alpine Ridge - a USB 3.2 Gen 2 downstream interface. Sabrent has taken advantage of this with a nifty tweak in the standard Thunderbolt 3 SSD reference design. The USB 3.2 Gen 2 downstream port is connected to the upstream interface of a USB to NVMe bridge chip (a Realtek 9210PD in all likelihood, though Tom's Hardware reports it as Realtek 9108B). Depending on the host to which the drive is connected (reported by the JHL7440), the PCIe 3.0 x4 lanes of the NVMe SSD are connected to either the JHL7440's downstream PCIe 3.0 x4 lanes or the Realtek bridge chip's PCIe 3.0 x4 lanes.

    The Sabrent Rocket XTRM-Q's compatibility with both Thunderbolt 3 and USB ports while providing different performance profiles made for an interesting evaluation exercise. The SSD also happens to be the first we have evaluated with Intel's Titan Ridge controller. Based on these aspects, we evaluated the XTRM-Q models as well as a host of other SSDs with the following host controllers:

      Additional details are available further down in the sub-section dealing with our testbed setup and evaluation methodology.

      The various graphs in this piece compare and contrast the performance of different external SSDs when used with different host ports. The complete list is provided below, with the host specified in brackets. Some entries do not have a host entry - the numbers presented for those are from its evaluation with our standard testbed using the Alpine Ridge (JHL6540) host.

        A quick overview of the internal capabilities of the storage devices is given by CrystalDiskInfo.