Akasa M.2 SSD Enclosures Reviewed: Giving Spare Drives a New Lease of Life
by Ganesh T S on September 22, 2021 8:00 AM ESTMiscellaneous Aspects and Concluding Remarks
The performance of the storage bridges 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 overall 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.
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The pure SATA bridge solution maintains a steady write speed of around 480 MBps after the initial 500 MBps SLC cache burst. The SSD temperature starts off at 31C before ending up at 68C after 30 minutes (the time taken to fill up 90% of the drive capacity). On the other hand, the multi-protocol solution is able to maintain the direct-to-TLC 480 MBps only for around 6 minutes before thermal throttling kicks in. Despite the throttling, the SSD temperature after 45 minutes was around 76C.
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The pure bridge (ASMedia ASM2362) solution is able to sustain 1GBps throughout the 14-odd minutes taken to fill up 90% of the drive capacity of the SK hynix Gold P31 1TB SSD. The temperature started off at 46C, before ending up at 62C. On the other hand, the absence of any thermal solution in the Realtek RTL9210B-CG solution makes the same SSD throttle. After sustaining 1GBps for around 5 minutes, the write transfer rate drops down to around 750 MBps for the remaining duration.
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 2.5W (500mA @ 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.
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The pure bridge solution is slightly more power efficient compared to the multi-protocol solution (peak of 3.92W vs. 4.15W, and around 0.2W - 0.3W delta in the operating power during active traffic)
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The ASMedia ASM2362 NVMe bridge solution configuration is significantly more power hungry compared to the multi-protocol Realtek RTL9210B-CG solution. The pure bridge solution consumes around 2.3W during active traffic and 1.5W at idle. In contrast, the Realtek solution consumes around 2W during active traffic and 1.2W / 0.4W at idle.
Market Availability and Pricing
Akasa distributes its SSD enclosures in multiple market regions. Unfortunately, they are not directly available in the North American market, with the focus in the US being more on their fanless PC cases.
In the UK, the pure SATA bridge (AK-ENU3M2-02) can purchase for GBP 25, and is also available in the US (shipped from UK) for $43. There are a large number of pure SATA bridge solutions available in the market - even ones using the same VIA Labs VL716 bridge. Depending on the market region, other similar options may be cheaper - such as this $16 one for US consumers.
The pure NVMe bridge (AK-ENU3M2-03) is available for GBP 60 or USD 50. The product doesn't seem to be as widely carried as the other two solutions. In any case, M.2 NVMe – USB-C bridge solutions are a dime a dozen nowadays. We have reviewed very effective and efficient solutions from MyDigitalSSD as well as Plugable (USD 50) previously. Cheaper options are available for this particular use-case.
The multi-protocol solution (AK-ENU3M2-04) is available for GBP 40. This is a unique product, and the only alternative we could find in the US market is the FIDECO M.2 NVMe & SATA SSD Enclosure Adapter for USD 31. The FIDECO model's case and main board seems to be exactly the same as the AK-ENU3M2-04 (possibly using the same OEM), though the bundled accessories are probably different. Readers in the US interested in the AK-ENU3M2-04 after reading this review can probably opt for the FIDECO model.
Final Words
Akasa's USB 3.2 Gen 2 (10Gbps) M.2 SSD enclosures lineup is quite comprehensive in terms of addressing various market requirements. The SATA-only and NVMe-only bridges are quite similar to other products in the market, and do not offer any compelling differentiation aspects. On the other hand, the multi-protocol solution in the AK-ENU3M2-04 is quite unique.
After using the AK-ENU3M2-04 heavily over the last couple of months, its pros and cons are quite clear. If performance is the sole requirement, the Realtek solution is not going to fit the bill. Rather, it shines as a tool for computer support technicians and people involved in frequently maintaining / servicing multiple PCs. In addition to supporting both SATA and NVMe SSDs, it also comes with both Type-A and Type-C connectors integrated. There is no need to carry around cables or search for the right cable when dealing with PCs that do not have a Type-C port. Essentially, it can act as a very high performance thumb drive. On the flip side, the absence of a thermal solution means that certain SSDs could get quite hot when subject to heavy traffic inside the enclosure. We have been using the SK hynix P31 in it, and the SSD throttles a bit only after more than 100GB of continuous writes. If heavy continuous traffic is expected, users can always opt to add their own thin thermal pad - the enclosure is aluminum and can easily conduct heat away.
Overall, Akasa's M.2 SSD enclosures lineup is quite comprehensive, with different products catering to different requirements. It is a pity that the company distributes only fanless PC cases in the NA region. Given the unique multi-protocol product in the lineup, we hope the company can start distributing them worldwide.
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ganeshts - Wednesday, September 22, 2021 - link
The Turing fanless case we reviewed last year is still doing great in deployment, and I don't think we have reviewed any Akasa gear after that. The storage bridges we reviewed in this article came in early last year, and the multi-protocol unit has been 'abused' greatly across multiple systems - has been working great for the last couple of months. The other two bridges were subject to only our evaluation process with a single host port, and that in itself is quite rigorous (multiple portable SSDs / storage bridges have experiences dropouts under heavy traffic, but no such issues with the Akasa bridges).Tomatotech - Thursday, September 23, 2021 - link
Thankfully I’ve successfully avoided buying any SATA m.2 drives. There must be people out there who were forced by circumstances into buying them, but I haven’t met any. Are there AnandTech readers out there who had to buy them?anad0commenter - Friday, September 24, 2021 - link
Does any of these work with the Plextor m6e AHCI PCIe m.2 SSD? It's one of the weirdest SSDs out there, which came out before NVMe became popular. And for the life of me, I can't find an enclosure that will work with it. SATA m.2 enclosures don't seem to be compatible.Tomatotech - Sunday, September 26, 2021 - link
I think you want an AHCI adaptor. It’s a little dongle about an inch wide that goes between the SSD and the m.2 socket. I’m not sure if we’re talking about the same thing here, but Apple used a weird type of SSD for several years 2013-2015ish. So there’s a bit of a market for adaptors to retrofit the Mac laptops so that they can use modern NVMe drives. I have 2 of these adaptors in my Mac laptops.The problem is the adaptors that are available are intended to let a modern nvme ssd fit into Apple’s weird socket (it was designed before the nvme standard was nailed down). What you’re after is an adaptor to let your weird drive fit into a modern socket. Good luck searching. I haven’t had much luck finding adaptors to let me re-use my surplus Apple OEM m.2(ish) drives as a portable ssd.
(Don’t want to sell my Apple OEM drives as some OS bootrom upgrades prefer the original drive in place.). TBH at this point in time I regard any non-NVMe ssd as a lost cause and effectively worthless, at least in the smaller sizes.
anad0commenter - Tuesday, September 28, 2021 - link
The adaptor was a good idea, but it turns out that it's only for macbooks, which use a 12+16 pin notch. So when I put the Plextor SSD on one side, the other side of the adaptor will not go into a standard m.2 slot which has a notch after 5 pins.There's a USB3.0 enclosure on ebay that claims it's AHCI NGFF compatible. But it costs $70!! Not sure if it's worth the risk to find out of it works with the Plextor....