Original Link: https://www.anandtech.com/show/16307/sabrent-rocket-xtrmq-usb-thunderbolt-3-dual-mode-external-ssd-review
Sabrent Rocket XTRM-Q USB / Thunderbolt 3 Dual Mode External SSD Review: Yin and Yang
by Ganesh T S on December 14, 2020 9:30 AM EST
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 increasing confidence of manufacturers in QLC (4-bits per cell) 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.
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 efforts with internal (M.2) products, 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:
- 2.5GBps+ class: Thunderbolt SSDs with PCIe 3.0 x4 NVMe drives
- 2GBps+ class: USB 3.2 Gen 2x2 SSDs with PCIe 3.0 x4 NVMe drives
- 1GBps+ class: USB 3.2 Gen 2 SSDs with PCIe 3.0 (x4 or x2) NVMe drives
- 500MBps+ class: USB 3.2 Gen 2 SSDs with SATA drives
- 400MBps+ class: USB 3.2 Gen 1 SSDs with SATA drives
- Sub-400MBps+ class: USB 3.2 Gen 1 flash drives with direct flash-to-USB controllers
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:
- Thunderbolt 3 : Intel Alpine Ridge (JHL6540)
- Thunderbolt 3 : Intel Titan Ridge (JHL 7540)
- USB 3.2 Gen 2 : ASMedia ASM2142
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.
- Sabrent Rocket XTRM-Q 4TB [JHL6540]
- Sabrent Rocket XTRM-Q 4TB [ASM2142]
- Crucial Portable SSD X8 2TB
- DIY TB3 SSD [TEKQ Rapide - WD Black SN750] [JHL6540]
- DIY TB3 SSD [TEKQ Rapide - WD Black SN750] [JHL7540]
- OWC Envoy Pro EX TB3 2TB [JHL6540]
- OWC Envoy Pro EX USB-C 2TB
- Plugable TBT3-NVME2TB 2TB [JHL6540]
- Sabrent Rocket Nano Rugged 2TB
- Sabrent Rocket XTRM-Q 2TB [ASM2142]
- Sabrent Rocket XTRM-Q 2TB [JHL6540]
- Sabrent Rocket XTRM-Q 2TB [JHL7540]
- Sabrent Rocket XTRM-Q 4TB [JHL7540]
- SanDisk Extreme PRO Portable SSD v2 2TB [ASM3242]
- SanDisk Extreme PRO Portable SSD v2 2TB [JHL6540]
A quick overview of the internal capabilities of the storage devices is given by CrystalDiskInfo.
| Drive Information |
 |
The Sabrent Rocket XTRM-Q uses standard PCIe 3.0 x4 NVMe drives internally. The bridge chip configuration allows for S.M.A.R.T passthrough and the SSDs support TRIM to maintain optimal performance. The internal SSD is actually the Sabrent Rocket Q that was reviewed earlier this month.
Testbed Setup and Testing Methodology
Evaluation of DAS units on Windows is done with a Hades Canyon NUC configured as outlined below. We use one of the rear USB Type-C ports enabled by the Alpine Ridge controller for both Thunderbolt 3 and USB devices. However, to force the usage of the USB 3.2 Gen 2 interface in the Rocket XTRM-Q, the SSD was connected to the front USB Type-C port enabled by the ASMedia ASM2142 controller.
| AnandTech DAS Testbed Configuration (JHL6540 and ASM2142 Hosts) | |
| Motherboard | Intel NUC8i7HVB |
| CPU | Intel Core i7-8809G Kaby Lake, 4C/8T, 3.1GHz (up to 4.2GHz), 14nm+, 8MB L2 |
| Memory | Crucial Technology Ballistix DDR4-2400 SODIMM 2 x 16GB @ 16-16-16-39 |
| OS Drive | Intel Optane SSD 800p SSDPEK1W120GA (118 GB; M.2 Type 2280 PCIe 3.0 x2 NVMe; Optane) |
| SATA Devices | Intel SSD 545s SSDSCKKW512G8 (512 GB; M.2 Type 2280 SATA III; Intel 64L 3D TLC) |
| Chassis | Hades Canyon NUC |
| PSU | Lite-On 230W External Power Brick |
| OS | Windows 10 Enterprise x64 (v1909) |
| Thanks to Intel for the build components | |
We also evaluated the performance of some of the Thunderbolt 3 SSDs with a Titan Ridge host - the Ghost Canyon NUC. These SSDs carry a JHL7540 tag in their graph entries. The configuration of the Ghost Canyon NUC used for benchmarking purposes is specified below.
| AnandTech DAS Testbed Configuration (JHL7540 Host) | |
| Motherboard | Intel NUC9i9QNB |
| CPU | Intel Core i9-9980HK Coffee Lake-H, 8C/16T, 2.4 (5.0) GHz, 14nm (optimized), 16MB L2+L3, 45W TDP |
| Memory | Corsair Vengeance DDR4-2666 SODIMM 2 x 16GB @ 18-19-19-39 |
| OS Drive | Intel SSD 905p Optane SSDPEL1D380GA (380 GB; M.2 Type 22110 PCIe 3.0 x4 NVMe; Optane / 3D XPoint) |
| Secondary Drive | Kingston KC2000 SKC2000M81000G (1TB; M.2 Type 2280 PCIe 3.0 x4 NVMe; Toshiba 96L 3D TLC; Silicon Motion SM2262EN Controller) |
| Chassis | Ghost Canyon NUC |
| PSU | FSP 500W 80 PLUS Platinum Internal Power Supply |
| OS | Windows 10 Enterprise x64 (v1909) |
| Thanks to Intel, Kingston, and Corsair for the build components | |
Our evaluation methodology for direct-attached storage devices adopts a judicious mix of synthetic and real-world workloads. While most DAS units targeting a particular market segment advertise similar performance numbers and also meet them for common workloads, the real differentiation is brought out on the technical side by the performance consistency metric and the effectiveness of the thermal solution. Industrial design and value-added features may also be important for certain users. The remaining sections in this review tackle all of these aspects after analyzing the features of the drives in detail.
Device Features and Characteristics
Sabrent packs its drives into metal cases, delivering the look and feel of a premium product. Inside the box, we have the main SSD and a box containing the cables - a USB 3.2 Gen 2 Type-C to Type-A one, and a Thunderbolt 3 Type-C to Type-C one. A note with directions to change the caching policy for the drive is also included, as shown in the picture below.
The write-caching policy problem is an issue for all Thunderbolt 3 SSDs in the market, and is not restricted to the Sabrent Rocket XTRM-Q. Despite the provided directions, we evaluate all SSDs (including our DIY Thunderbolt 3 SSD using the TEKQ Rapide enclosure and the WD Black SN750) in the default state with write caching turned off - This ensures we are comparing apples to apples even when the units under consideration use different host interfaces.
The Sabrent Rocket XTRM-Q is bundled with the longest Thunderbolt 3 cable (70cm) we have seen so far in any Thunderbolt 3 SSD. Sabrent also provides optional shockproof protection in the form of bumpers for the XTRM-Q. At less than 130g, the drives are light but the aluminum enclosure lends solidity.
The table below compares the features and characteristics of the various SSDs dealt with in the review today.
| Direct-Attached Storage Characteristics | ||
| Aspect | ||
| Upstream Port | USB 3.2 Gen 2 and Thunderbolt 3 Type-C | USB 3.2 Gen 2 Type-C |
| Bridge / Controller | Intel JHL7440 + Phison E12S-based Sabrent Rocket Q | ASMedia ASM2362 + Silicon Motion SM2263 |
| Flash | Micron 96L 3D QLC | Micron 96L 3D QLC |
| Power | Bus Powered | Bus Powered |
| Physical Dimensions | 190 mm x 132 mm x 17.53 mm | 110 mm x 53 mm x 11.5 mm |
| IP Rating | N/A | N/A |
| Weight | 129 grams (without cable) | 101 grams (without cable) |
| Cable | ~50cm USB 3.2 Gen 2 Type-C to Type-A ~70cm Thunderbolt 3 (Type-C to Type-C) |
23 cm USB 3.2 Gen 1 Type-C to Type-C Type-C to Type-A adaptor bundled |
| S.M.A.R.T Passthrough | Yes | Yes |
| UASP Support | Yes | Yes |
| TRIM Passthrough | Yes | Yes |
| Encryption Support | N/A | N/A |
The Sabrent Rocket XTRM-Q is available in capacities ranging from 500GB (with a MSRP of $230) to 8TB (with a MSRP of $2000). This high capacity is achieves thanks to the use of Micron's 96L QLC NAND. QLC brings along a host of challenges related to endurance and slow write speeds. SSD vendors solve this by bringing in overprovisioning and SLC caching. Sabrent indicated that the XTRM-Q models come with around 9% over-provisioning out of the box. SLC cache size varies based on the drive capacity, and that is one of the aspects we evaluate further down in this review.
Synthetic Benchmarks - ATTO and CrystalDiskMark
Sabrent claims speeds in excess of 2500MBps for the Rocket XTRM-Q. This is backed up by the ATTO benchmarks provided below on the read side, but the absence of write caching results in sub-1GBps performance for writes using the Thunderbolt 3 host ports. There is no discernible difference in the performance numbers when using either the JHL6540 or JHL7540 host. However, in the USB mode, the drives come close to 1GBps for both reads and writes (using the ASMedia ASM2142 host). These observations are common to both the 2TB and 4TB variants of the Rocket XTRM-Q. It must be noted that these access traces are not very common in real-life scenarios.
| Drive Performance Benchmarks - CrystalDiskMark |
 |
In CrystalDiskMark, we see the 4TB version actually perform a bit worse compared to the 2TB version in the sequential reads with the Thunderbolt 3 host ports. However, in USB mode, both versions perform very similar to each other. In the USB mode, we can compare the 2TB version against the Crucial X8 for an apples-to-apples comparison - the numbers are in favor of the XTRM-Q across multiple traces.
In the next section, we take a look at real-world workloads along with an evaluation of the performance consistency.
AnandTech DAS Suite - Benchmarking for Performance Consistency
Our testing methodology for DAS units takes into consideration the usual use-case for such devices. The most common usage scenario is transfer of large amounts of photos and videos to and from the unit. Other usage scenarios include the use of the DAS as a download or install location for games and importing files directly off the DAS into a multimedia editing program such as Adobe Photoshop. Some users may even opt to boot an OS off an external storage device.
The AnandTech DAS Suite tackles the first use-case. The evaluation involves processing three different workloads:
- Photos: 15.6 GB collection of 4320 photos (RAW as well as JPEGs) in 61 sub-folders
- Videos: 16.1 GB collection of 244 videos (MP4 as well as MOVs) in 6 sub-folders
- BR: 10.7 GB Blu-ray folder structure of the IDT Benchmark Blu-ray
Each workload's data set is first placed in a 25GB RAM drive, and a robocopy command is issued to transfer it to the DAS under test (formatted in NTFS). Upon completion of the transfer (write test), the contents from the DAS are read back into the RAM drive (read test). This process is repeated three times for each workload. Read and write speeds, as well as the time taken to complete each pass are recorded. Bandwidth for each data set is computed as the average of all three passes.
| Performance Consistency and Thermal Characteristics |
 |
The first three sets of writes and reads correspond to the photos suite. A small gap (for the transfer of the video suite from the internal SSD to the RAM drive) is followed by three sets for the video suite. Another small RAM-drive transfer gap is followed by three sets for the Blu-ray folder. An important point to note here is that each of the first three blue and green areas correspond to 15.6 GB of writes and reads respectively. The low write speeds with Thunderbolt 3 hosts are evident in the graphs, but they are remarkably consistent across different sets of workloads pointing to the SLC cache not running out for this traffic pattern. The thermal design is also excellent - the internal SSD temperaturee goes slightly north of 50C in only one of the six graphs of interest above.
PCMark 10 Storage Bench - Real-World Access Traces
There are a number of storage benchmarks that can subject a device to artificial access traces by varying the mix of reads and writes, the access block sizes, and the queue depth / number of outstanding data requests. We saw results from two popular ones - ATTO, and CrystalDiskMark - in a previous section. More serious benchmarks, however, actually replicate access traces from real-world workloads to determine the suitability of a particular device for a particular workload. Real-world access traces may be used for simulating the behavior of computing activities that are limited by storage performance. Examples include booting an operating system or loading a particular game from the disk.
PCMark 10's storage bench (introduced in v2.1.2153) includes four storage benchmarks that use relevant real-world traces from popular applications and common tasks to fully test the performance of the latest modern drives:
- The Full System Drive Benchmark uses a wide-ranging set of real-world traces from popular applications and common tasks to fully test the performance of the fastest modern drives. It involves a total of 204 GB of write traffic.
- The Quick System Drive Benchmark is a shorter test with a smaller set of less demanding real-world traces. It subjects the device to 23 GB of writes.
- The Data Drive Benchmark is designed to test drives that are used for storing files rather than applications. These typically include NAS drives, USB sticks, memory cards, and other external storage devices. The device is subjected to 15 GB of writes.
- The Drive Performance Consistency Test is a long-running and extremely demanding test with a heavy, continuous load for expert users. In-depth reporting shows how the performance of the drive varies under different conditions. This writes more than 23 TB of data to the drive.
Despite the data drive benchmark appearing most suitable for testing direct-attached storage, we opted to run the full system drive benchmark as part of our evaluation flow. Many of us use portable flash drives as boot drives and storage for Steam games. These types of use-cases are addressed only in the full system drive benchmark.
The Full System Drive Benchmark comprises of 23 different traces. For the purpose of presenting results, we classify them under five different categories:
- Boot: Replay of storage access trace recorded while booting Windows 10
- Creative: Replay of storage access traces recorded during the start up and usage of Adobe applications such as Acrobat, After Effects, Illustrator, Premiere Pro, Lightroom, and Photoshop.
- Office: Replay of storage access traces recorded during the usage of Microsoft Office applications such as Excel and Powerpoint.
- Gaming: Replay of storage access traces recorded during the start up of games such as Battlefield V, Call of Duty Black Ops 4, and Overwatch.
- File Transfers: Replay of storage access traces (Write-Only, Read-Write, and Read-Only) recorded during the transfer of data such as ISOs and photographs.
PCMark 10 also generates an overall score, bandwidth, and average latency number for quick comparison of different drives. The sub-sections in the rest of the page reference the access traces specified in the PCMark 10 Technical Guide.
Booting Windows 10
The read-write bandwidth recorded for each drive in the boo access trace is presented below.
The overall scores reflect our inferences from the previous set of tests - the 2TB performs better than the 4TB version for the most part, and the USB mode delivers competitive performance (again, for the 2TB version in particular). When compared against other Thunderbolt 3 SSDs, the performance numbers are strictly average.
Consistency, Power, & Closing Remarks
The performance of the drives in various real-world access traces as well as synthetic workloads was brought out in the preceding sections. We also looked at the performance consistency for these cases. Power users may also be interested in performance consistency under worst-case conditions, as well as drive power consumption. The latter is also important when the drives are used with battery powered devices such as notebooks and smartphones. Pricing is also an important aspect. We analyze each of these in detail below.
Worst-Case Performance Consistency
Flash-based storage devices tend to slow down in unpredictable ways when subject to a large number of small-sized random writes. Many benchmarks use that scheme to pre-condition devices prior to the actual testing in order to get a worst-case representative number. Fortunately, such workloads are uncommon for direct-attached storage devices, where workloads are largely sequential in nature. Use of SLC caching as well as firmware caps to prevent overheating may cause drop in write speeds when a flash-based DAS device is subject to sustained sequential writes.
Our Sequential Writes Performance Consistency Test configures the device as a raw physical disk (after deleting configured volumes). A fio workload is set up to write sequential data to the raw drive with a block size of 128K and iodepth of 32 to cover 90% of the drive capacity. The internal temperature is recorded at either end of the workload, while the instantaneous write data rate and cumulative total write data amount are recorded at 1-second intervals.
| Drive Power Consumption - CrystalDiskMark Workloads |
 |
In the Thunderbolt 3 mode, the 4TB version operates between 2.08W and 6.02W with the JHL6540 and 2.01W and 9.23W with the JHL7540. The corresponding numbers for the 2TB drive are (2.07W, 6.76W) and (2.01W, 6.56W). In the USB mode, the 4TB drive operates between 1.11W and 5.19W, while the 2TB version operates between 1.10W and 5.19W. The power consumption in the USB mode is acceptable, though we have seen external SSDs from Samsung that enter lower power states quite frequently (enabling them to work well with battery-powered devices). In the Thunderbolt mode, the power consumption is lower than our DIY configuration, and approximately in the same ballpark as the other Thunderbolt 3 SSDs we are comparing them against.
Pricing
The price of flash-based storage devices tend to fluctuate quite a bit over time. However, the relative difference between different models usually doesn't change. The table below summarizes the product links and pricing for the various units discussed in the review.
| External Flash Storage Devices - Pricing | ||||
| Product | Model Number | Capacity (GB) | Street Price (USD) | Price per GB (USD/GB) |
| Crucial Portable SSD X8 2TB | CT2000X8SSD9 | 2000 | $307 | 0.153 |
| Sabrent Rocket Nano Rugged 2TB | SB-2TB-NAWP | 2000 | $330 | 0.165 |
| Sabrent Rocket XTRM-Q 2TB | SB-XTMQ-2TB | 2000 | $350 | 0.175 |
| Sabrent Rocket XTRM-Q 4TB | SB-XTMQ-4TB | 4000 | $700 | 0.175 |
| SanDisk Extreme PRO Portable SSD v2 2TB | SDSSDE81-2T00 | 2000 | $350 | 0.175 |
| OWC Envoy Pro EX USB-C 2TB | ENVPROC2N20 | 1920 | $349 | 0.182 |
| OWC Envoy Pro EX TB3 2TB | OWCTB3ENVP20 | 2000 | $480 | 0.24 |
| DIY TB3 SSD [TEKQ Rapide - WD Black SN750] | OWCTB3ENVP20 | 1000 | $245 | 0.245 |
| Plugable TBT3-NVME2TB 2TB | TBT3-NVME2TB | 2000 | $499 | 0.249 |
The Sabrent Rocket XTRM-Q drives are the cheapest Thunderbolt 3 SSDs in the market by a huge margin – In fact, the Plugable TBT3-NVME2TB and the OWC Envoy Pro EX TB3 2TB drives cost at least $130 more than the 2TB XTRM-Q. This is the first drive we have seen with QLC delivering the promised low-priced high-capacity SSD from a consumer perspective. The 4TB version has the same cost per GB, but its high capacity makes it a premium product with a $700 price tag.
Final Words
The Sabrent Rocket XTRM-Q represents a unique product line in the market – a dual-mode SSD that can work with both Thunderbolt 3 ports and USB ports with optimal performance profiles based on the host to which the drive is connected. It is also available in capacities that no other external SSD vendor offers. These two aspects ensure that the XTRM-Q can appeal to a select audience in a way that no other offering can match. Pricing is also attractive on a $-per-GB basis, and the thermal solution is excellent.
The use of QLC NAND could be a turn-off for some folks, though Sabrent has sought to address that with a liberal amount of SLC cache – almost 25% of the drive capacity. Unfortunately, there seem to be other problems – or at least quirks – on the write caching front. For medium-sized sustained writes, there's a sizable gap in performance between Thunderbolt 3 and USB modes, leaving the normally more capable Thunderbolt 3 mode at a disadvantage. This disappointing write performance in Thunderbolt 3 mode is quite puzzling – given that these slow write speeds don't occur in USB mode, it hints that SLC write caching is not being under in Thunderbolt 3 mode. But even then, our DIY configuration with the same write caching functionality turned off is able to deliver much better numbers.
Overall, although the Rocket XTRM-Q is a dual-mode drive, it has a distinct yin and yang dichotomy going on, which depends on the host type. As a Thunderbolt 3 device the drive can put up some great read speeds, which is what you'd expect with an NVMe-based drive backed by Thunderbolt 3's raw bandwidth. However write performance very clearly favors USB mode, as this is the only mode that seems to be able to take advantage of the drive's speedy SLC cache. It's strangely unbalanced performance that partially undermines what would otherwise should be the drive's biggest strength: a USB drive that's able to upgrade to Thunderbolt 3 for even better performance on compatible hosts.
Thunderbolt 3 performance aside, it's also unfortunate that the internal SSD is pretty much inaccessible. The unit as a whole is sealed shut, which means that in case of an unlikely board or bridge chip failure, the ability to recover data by attaching the internal drive to another computer is pretty much ruled out. Other than the Crucial Portable X6 and X8, we haven't seen any of the other external SSDs (with the flash and bridge chips on separate boards) keep their internal drive out of reach. Hopefully, this is an aspect that Sabrent can address in the future.
Otherwise, Sabrent would also do well to release a 3D TLC version of the dual-mode platform to address some of the shortcomings of the XTRM-Q while retaining the positives. This is likely still a generation off (we've yet to see the prerequisite 8TB TLC M.2 drives), but it would help boost the drive's minimum write performance, which it never hurts to improve on.
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