Samsung T9 Portable SSD Review: A 20 Gbps PSSD for Prosumer Workloads

Benchmarks such as ATTO and CrystalDiskMark help provide a quick look at the performance of the direct-attached storage device. The results translate to the instantaneous performance numbers that consumers can expect for specific workloads, but do not account for changes in behavior when the unit is subject to long-term conditioning and/or thermal throttling. Yet another use of these synthetic benchmarks is the ability to gather information regarding support for specific storage device features that affect performance.

Samsung claims speeds of up to 2000 MBps for the T9 4TB version. Our ATTO testing configuration manages to reach numbers quite close to the advertised one for reads, while the writes are a bit lower. However, we only use a single queue depth of 4 – so, it is only representative of a small subset of real-world workloads. It does allow the visualization of change in transfer rates as the I/O size changes, with optimal performance being reached around 1 MB for a queue depth of 4.

ATTO Benchmarks
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CrystalDiskMark uses four different access traces for reads and writes over a configurable region size. Two of the traces are sequential accesses, while two are 4K random accesses. Internally, CrystalDiskMark uses the Microsoft DiskSpd storage testing tool. The ‘Seq128K Q32T1’ sequential traces use 128K block size with a queue depth of 32 from a single thread, while the ‘4K Q32T16’ one does random 4K accesses with the same queue configuration, but from multiple threads. The ‘Seq1M’ traces use a 1MiB block size. The plain ‘Rnd4K’ one uses only a single queue and single thread . Comparing the ‘4K Q32T16’ and ‘4K Q1T1’ numbers can quickly tell us whether the storage device supports NCQ (native command queuing) / UASP (USB-attached SCSI protocol). If the numbers for the two access traces are in the same ballpark, NCQ / UASP is not supported. This assumes that the host port / drivers on the PC support UASP.

CrystalDiskMark Benchmarks
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The writes fall short of Samsung’s claims, but the PSSD is indeed able to reach 2000 MBps for large-sized reads. Both NCQ and UASP are supported. Since the base platform is a DRAM-less NVMe SSD, the random access numbers are not as good as what can be obtained with a DRAM-equipped PSSD such as the SanDisk Extreme PRO v2.

AnandTech DAS Suite – Benchmarking for Performance Consistency

Our testing methodology for storage bridges / direct-attached storage 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 unit as a download or install location for games and importing files directly from it 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 five different workloads:

• AV: Multimedia content with audio and video files totaling 24.03 GB over 1263 files in 109 sub-folders
• Home: Photos and document files totaling 18.86 GB over 7627 files in 382 sub-folders
• BR: Blu-ray folder structure totaling 23.09 GB over 111 files in 10 sub-folders
• ISOs: OS installation files (ISOs) totaling 28.61 GB over 4 files in one folder
• Disk-to-Disk: Addition of 223.32 GB spread over 171 files in 29 sub-folders to the above four workloads (total of 317.91 GB over 9176 files in 535 sub-folders)

Except for the ‘Disk-to-Disk’ workload, each data set is first placed in a 29GB RAM drive, and a robocopy command is issue to transfer it to the external storage unit (formatted in exFAT for flash-based units, and NTFS for HDD-based units).

robocopy /NP /MIR /NFL /J /NDL /MT:32 $SRC_PATH $DEST_PATH

Upon completion of the transfer (write test), the contents from the unit are read back into the RAM drive (read test) after a 10 second idling interval. 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. Whenever possible, the temperature of the external storage device is recorded during the idling intervals. Bandwidth for each data set is computed as the average of all three passes.

The ‘Disk-to-Disk’ workload involves a similar process, but with one iteration only. The data is copied to the external unit from the CPU-attached NVMe drive, and then copied back to the internal drive. It does include more amount of continuous data transfer in a single direction, as data that doesn’t fit in the RAM drive is also part of the workload set.

The Samsung T9 marks its entry in the middle or lower half of the pack in all of the cases above. There are two contributing factors here – PSSDs with DRAM perform inherently better when bombarded with accesses, and the direct-to-TLC write speeds for the 6th Gen. V-NAND used in the T9 are probably not as good as those for the other NAND used in other PSSDs in the above graphs.

Performance Consistency

Aspects influencing the performance consistency include SLC caching and thermal throttling / firmware caps on access rates to avoid overheating. This is important for power users, as the last thing that they want to see when copying over 100s of GB of data is the transfer rate going down to USB 2.0 speeds.

In addition to tracking the instantaneous read and write speeds of the DAS when processing the AnandTech DAS Suite, the temperature of the drive was also recorded. In earlier reviews, we used to track the temperature all through. However, we have observed that SMART read-outs for the temperature in NVMe SSDs using USB 3.2 Gen 2 bridge chips end up negatively affecting the actual transfer rates. To avoid this problem, we have restricted ourselves to recording the temperature only during the idling intervals. The graphs below present the recorded data.

AnandTech DAS Suite – Performance Consistency
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The first three sets of writes and reads correspond to the AV 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 Home suite. Another small RAM-drive transfer gap is followed by three sets for the Blu-ray folder. This is followed up with the large-sized ISO files set. Finally, we have the single disk-to-disk transfer set.

The T9 has very good performance consistency, with the SLC cliff barely seen in the RAM drive transfer sets. However, there is a sharp drop down to 900 MBps from 1.5 GBps in the disk-to-disk transfer set. That said, the temperature profile of the PSSD is very good, with the internals at 50C at the end of the transfer routine.

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 opt 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 mixture of access traces triggered by this workload is well serviced by dedicated NVMe SSD controllers – so we see the PSSDs based on native flash controllers in the lower half. The T9 makes a respectable entry by being better than the P50 from 2020. However, it is left way behind by the PSSDs using DRAM-equipped NVMe drives.

Creative Workloads

The read-write bandwidth recorded for each drive in the sacr, saft, sill, spre, slig, sps, aft, exc, ill, ind, psh, and psl access traces are presented below.

The T9 does not deliver exceptional performance for any of these workloads, but at the same time, it manages to place itself in the middle of the pack.

Office Workloads

The read-write bandwidth recorded for each drive in the exc and pow access traces are presented below.

The presence of a Phison U17 drive in the comparison list helps save the T9 from making up the rear of the pack. The Powerpoint workload, in particular, is handled quite poorly by the T9.

Gaming Workloads

The read-write bandwidth recorded for each drive in the bf, cod, and ow access traces are presented below.

The scenario seen for the Office workloads plays out here also, with only the PNY EliteX-PRO faring worse for these read-intensive use-cases.

Files Transfer Workloads

The read-write bandwidth recorded for each drive in the cp1, cp2, cp3, cps1, cps2, and cps3 access traces are presented below.

The T9 performs moderately well here, and the presence of reads in the midst of write pressure exposes the shortcomings in the native flash controller-based PSSDs. Still, the T9 is not able to surpass the performance of DRAM-equipped drives.

Overall Scores

PCMark 10 reports an overall score based on the observed bandwidth and access times for the full workload set. The score, bandwidth, and average access latency for each of the drives are presented below.

The T9 finds itself in the bottom half of the pack, but the absolute scores for all PSSDs without DRAM are fairly close to each other.

The performance of the PSSDs in various real-world access traces as well as synthetic workloads was brought out in the preceding section. 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
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The T9 is able to ingest data at the highest possible speeds for up to 105s continuously. After that, the pseudo-SLC cache of around 175 GB gets filled up, and speeds drop down to around 900 MBps. If the user workload is going to be less than 175 GB, this is not a concern at all. The thermal profile in this test is also excellent. With the temperature ending up at 52C, it is matched only by the SanDisk Extreme PRO PSSD v2’s 58C, with the rest heating up to more than 65C despite having much steeper SLC cliffs. Overall, the direct-to-TLC writes could have been faster on the bandwidth front. On the thermal solution side, there is absolutely no cause for complaint.

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 ChargerLAB KM003C, 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
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The peak power consumption (6.7W) is quite competitive against all other PSSDs that are not based on native flash controllers. The lowest idle power number of 0.25W is also the least among such PSSDs. However, the PSSDs based on controllers like the Phison U18 and Silicon Motion SM2320 have a true deep-sleep mode where the bus power consumption is essentially non-existent. Unfortunately, the Samsung T9 doesn’t seem to have such a mode.

Final Words

The Samsung Portable SSD T9 is available for purchase today, with suggested pricing of $140 for the 1 TB version, $240 for the 2 TB, and $440 for the 4 TB SKU. At these prices, the value proposition does not look good for the T9. The SanDisk Extreme PRO v2 that wins out on most of the benchmarks, and has similar thermal profile is priced at $300. We are aware that recent batches of the SanDisk PSSD have resulted in extreme consumer dissatisfaction, but we believe Western Digital has already addressed the problem if they are confident enough to continue selling it. The Crucial X10 Pro 4 TB is priced at $290, but we have not included it in the comparison list in this review, as that PSSD is still under evaluation. The other PSSDs are all based on native controllers and can’t match the T9’s performance profile. Despite their much lower price points, they do not contribute to the comparative value proposition discussion.

The Samsung Portable SSD T9 is a valuable addition to the company’s T series lineup. It retains the sleek and attractive form-factor of its predecessors, and also adds some ruggedness with its re-designed rubber sleeve. Subjectively speaking, the new sleeve with its carbon pattern design is more functional and provides a solid feel in the hand compared to the T7 Shield.

The T9’s pseudo-SLC cache size of around 175 GB is more than enough for most consumers, and likely for a large number of prosumers too. It needs to be noted that a USB 3.2 Gen 2×2 host is needed to take full benefit of the PSSD’s performance. However, thanks to USB’s backward compatibility, the T9 can be used with a wide variety of systems – including those with just USB 2.0 ports.

Samsung is also releasing a new version of their Magician software this month. The new version unifies the product maintenance aspect for a range of internal SSDs, memory cards, and PSSDs as well. This will also include data migration support, counterfeit checking capabilities, and the ability to set a password for the drive (and take advantage of the hardware encryption capabilities).

Compared to the Samsung X5, the T9 is able to perform reasonably well across our entire test suite. The launch pricing is a bit out of touch with market reality (given the price of the 20 Gbps PSSDs from Samsung’s competitors). Pricing the T9 4 TB version around $300 would have resulted in a much better value proposition. As it stands, the performance of the T9 is passable given its DRAM-less nature. Had Samsung opted for a DRAM-equipped NVMe SSD component with the latest NAND instead of retaining the one from the T7 Shield, the T9 could have even be in the competition for the performance crown.