Transcend ESD310C Dual-Interface UFD Review: Silicon Motion Powers Portable SSD in a Thumb Drive

Miscellaneous Aspects and Concluding Remarks

The performance of the Transcend ESD310C portable SSD 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 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.

Sequential Writes to 90% Capacity - Performance Consistency
TOP: Transcend ESD310C 1TBOWC Envoy Pro Elektron 1TBOWC Envoy Pro Mini 1TBKingston DTMAXA/1TBSamsung T7 Touch 1TBKingston DT Max 1TB	BOTTOM: OWC Envoy Pro Elektron 1TBOWC Envoy Pro Mini 1TBKingston DTMAXA/1TBSamsung T7 Touch 1TBKingston DT Max 1TBTranscend ESD310C 1TB

There are two main comparisons of interest - the first one is against the Kingston DTMAX A, because of the presence of the same controller and NAND flash in both products. The second one is the OWC Envoy Pro Mini, because it is a dual-interface UFD with a native controller too, albeit one based on a Phison controller.

The Transcend ESD310C starts off at peak speeds of 760 MBps (for the tested queue depth and transfer size) and maintains it for around 115s (total SLC cache of around 85 GB). After that, the write speed stabilizes around 60 MBps taking around 12300 seconds to complete the workload. The temperature at the end was just 60 C, which points to thermal throttling at play to keep the UFD skin temperature in check. On the other hand, the Kingston DTMAX A exhibits a range of speeds from 50 MBps to 650 MBps - very inconsistent, but manages to complete the workload in around 7400s. The OWC Envoy Pro Mini, which clocked in last in all the performance benchmarks, redeems itself admirably in this stress test. It completed the workload in the fastest time - 3630s, and exhibited only three distinct speed levels - 770 MBps, 270 MBps, and 220 MBps, with the first cliff happening at around 25 GB (SLC cache).

From a sequential data dump perspective, the Transcend ESD310C 1 TB version emerges as a good candidate for up to 85 GB of writes at a time - even better than the Kingston DTMAX A. Beyond that, the DTMAX A's temperature cap of 80C+ lends it an advantage despite inconsistent speeds. However, the best dual-interface thumb drive for extended use with heavy writes is the OWC Envoy Pro Mini.

Power Consumption

Bus-powered devices can configure themselves to operate within the power delivery constraints of the host port. While Thunderbolt ports are guaranteed to supply up to 15W for client devices, USB 2.0 ports are guaranteed to deliver only 4.5W (900mA @ 5V). In this context, it is interesting to have a fine-grained look at the power consumption profile of the various external drives. Using the Plugable USBC-TKEY, the bus power consumption of the drives was tracked while processing the CrystalDiskMark workloads (separated by 5s intervals). The graphs below plot the instantaneous bus power consumption against time, while singling out the maximum and minimum power consumption numbers.

CrystalDiskMark Workloads - Power Consumption
TOP: Transcend ESD310C 1TBOWC Envoy Pro Elektron 1TBOWC Envoy Pro Mini 1TBKingston DTMAXA/1TBSamsung T7 Touch 1TBKingston DT Max 1TB	BOTTOM: OWC Envoy Pro Elektron 1TBOWC Envoy Pro Mini 1TBKingston DTMAXA/1TBSamsung T7 Touch 1TBKingston DT Max 1TBTranscend ESD310C 1TB

The Transcend ESD310C idles at around 0.77W, and has a peak power consumption of 2.28W. The Kingston DTMAX A with similar components (but only a Type-A interface, instead of Type-A + Type-C) idles at approximately the same number and has a peak of 2.31W. However, one important firmware configuration difference appears to be in the entry to a lower power consumption deep-sleep state after a period of inactivity. While the Kingston DTMAX A essentially turns off after 20 minutes or so of inactivity, the ESD310C doesn't. This may be a matter of concern for use with mobile devices, particularly if the user has a tendency to let the UFD remain connected to the USB port after use.

The power consumption numbers are obviously much lower than that of bridge-based solutions like the Samsung T7 Touch and OWC Elektron. The absolute numbers are also lower than the ones for the Phison-based OWC Envoy Pro Mini, and there are no idling period 'garbage-collection spikes' in the power consumption.

Final Words

The Transcend ESD310C was introduced in April 2023 and is slowly making its way to retailers around the world. In the North American market, the SKUs are available on Newegg, with the 1 TB version retailing for $68. The 512 GB and 256 GB versions are available for $49 and $35 respectively. The 2 TB version has been announced, but is not available in retail yet. The main comparison point here in the dual-interface class is the OWC Envoy Pro Mini. The 1 TB version of the OWC UFD retails for $125 - almost double that of the Transcend product. Despite targeting the same dual-interface market, the two products are meant to appeal to different consumer classes. The Transcend ESD310C should satisfy the requirements of most mainstream consumers - folks who don't expect to transfer 100s of GBs in one shot to the UFD. On the other hand, the OWC Envoy Pro Mini does have its own value proposition for prosumers with its unparalleled thermal design and excellent performance consistency under worst-case conditions.

After going through Silicon Motion's pitch for the Transcend ESD310C, I was only mildly interested - as we had already evaluated the performance of the SM2320 UFD in multiple avatars earlier - starting with the controller preview using a Gen 2x2 interface in a bare board and Micron's 96L 3D TLC, and moving on to various Kingston products such as the XS2000 (same NAND and Gen 2x2 interface, albeit with a proper thermal solution and firmware configuration changes), DataTraveler Max (same NAND, but a Gen 2 interface in a thumb drive form factor), and the DataTraveler Max Type-A (Kioxia BiCS5 112L 3D TLC and Gen 2 interface in a thumb drive form factor). Phison's native UFD controllers such as the U17 and U18 have understandable not created as much of an impact as the SM2320 in the PSSD market, but OWC had delivered something compelling using a Phison platform in the Envoy Pro Mini with its dual-interface design. With the Transcend ESD310C, Silicon Motion has shown that its controller can be used in products providing similar connectivity features.

Transcend's industrial design and firmware configuration for the ESD310C has enabled a much lower price point compared to the OWC Envoy Pro Mini. As outlined in different performance sub-sections, the knobs that have been tweaked (such as the SLC cache size, temperature cap for thermal throttling, etc.) make the product suitable for certain use-cases, and a middling performer in others.

Our recommendation for prosumers looking to purchase a dual-interface thumb drive continues to be the OWC Envoy Pro Mini. However, at around half its price and with a more compact design, the Transcend ESD310C makes a compelling case for the mainstream users.