Adata Legend 970 Pro SSD review: More pretender than contender

 Comparison Products 

Where to begin with the competition? We think the Crucial T705 is the drive to beat when it comes to high-end PCIe 5.0 SSDs. It even comes with a heatsink option. An honorable mention is the Sabrent Rocket 5, which has higher sustained write performance.

Adata does have a drive with the same controller as those two, the regular Legend 970, but it doesn't have the fastest variant of hardware. Adata went with an SMI controller in the Legend 960 Max and it’s good to see variety in the market again with InnoGrit on the 970 Legend Max. The Legend 960 Max was up against the Samsung 990 Pro, WD Black SN850X, and SK hynix Platinum P41 when it arrived. Those are among the fastest PCIe 4.0 drives on the market, along with the later-arriving Crucial T500.

For budget drives, we have the Samsung 990 EVO, which has the distinction of technically being a PCIe 5.0 drive as well (just with two lanes), since it can operate in two different modes. That said, we think Phison’s DRAM-less hardware makes for a better budget drive, represented by the Sabrent Rocket 4. Then there are the popular Maxio MAP1602 and YMTC flash mixes, such as with the Silicon Power US75. While the most popular of these use TLC flash, we’ve also seen QLC flash on the HP FX700, which would be a choice to potentially save a little money.

Let’s see how the Legend 970 Pro stacks up against all these competitors.

Trace Testing — 3DMark Storage Benchmark

Built for gamers, 3DMark’s Storage Benchmark focuses on real-world gaming performance. Each round in this benchmark stresses storage based on gaming activities including loading games, saving progress, installing game files, and recording gameplay video streams. Future gaming benchmarks will be DirectStorage-inclusive and we also include notes about which drives may be future-proofed.

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In this first matchup, we think it’s fair to say that Phison’s controller in the T705 beats InnoGrit’s in the Legend 970 Pro. Both drives have the same flash, so this is not a debate. It’s likely that Phison knows how to optimize for benchmarks, which should be taken into consideration. We would not recommend splurging on either drive for gaming as you can get sufficient performance from less expensive drives, like the Rocket 4. We’re also not yet at the stage where DirectStorage plays a significant role.

Trace Testing — PCMark 10 Storage Benchmark

PCMark 10 is a trace-based benchmark that uses a wide-ranging set of real-world traces from popular applications and everyday tasks to measure the performance of storage devices. The results are particularly useful when analyzing drives for their use as primary/boot storage devices and in work environments.

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Our PCMark 10 results continue to tell the same tale: The T705 dominates, and the 970 Pro doesn’t pull far away enough from fast PCIe 4.0 SSDs. It's possible that a high-end drive could provide better workstation performance, although raw application performance would not be the priority in picking a PCIe 5.0 drive over less expensive options. We would consider looking at wider performance bands with write saturation and CrystalDiskMark tests, as well as power efficiency in mobile cases.

Console Testing — PlayStation 5 Transfers

The PlayStation 5 is capable of taking one additional PCIe 4.0 or faster SSD for extra game storage, with some requirements. While any 4.0 drive will work, Sony recommends drives that can deliver at least 5,500 MB/s of sequential read bandwidth and will flash up a warning if your SSD doesn't break that mark in the built-in read test. The PS5 does not support the host memory buffer (HMB) feature but DRAM-less drives will still work fine. In our testing, PCIe 5.0 SSDs don't bring much to the table and preferably should not be used in the PS5, especially as they may require additional cooling. Please see our Best PS5 SSDs article for more information.

Our testing utilizes the PS5’s internal storage test and manual read/write tests with over 192GB of data both from and to the internal storage. Throttling is prevented where possible to see how each drive operates under ideal conditions. While game load times should not deviate much from drive to drive, our results can indicate which drives may be more responsive in long-term use.

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We do not recommend using a PCIe 5.0 drive in the PS5, especially if it doesn’t come with a heatsink. The Legend 970 does, and luckily it somewhat fits as well — beware drives with coolers that are too large. If you’re so inclined, this drive will work in a PS5, but its performance is not exemplary in any way. We would instead recommend the least expensive drive possible for your desired capacity, with the Teamgroup MP44 being a good choice from our Best SSDs list. Better yet, get a drive with a heatsink to prevent throttling, with drives from that list or our best PS5 SSDs list.

Transfer Rates — DiskBench

We use the DiskBench storage benchmarking tool to test file transfer performance with a custom, 50GB dataset. We write 31,227 files of various types, such as pictures, PDFs, and videos to the test drive, then make a copy of that data to a new folder, and follow up with a reading test of a newly-written 6.5GB zip file. This is a real world type workload that fits into the cache of most drives.

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The Legend 970 Pro has good read and write performance, as would be expected from a PCIe 5.0 SSD. Such a drive simply provides a higher transfer speed thanks to its faster interface. The same is true of the T705. That said, copy performance as a whole isn’t too impressive on the Legend 970 Pro, as even some good PCIe 4.0 SSDs can rival it. We still think that in general use the drive will provide more “oomph” than a budget SSD, but it’s not a particularly compelling upgrade if you already have a relatively fast drive.

Synthetic Testing — ATTO / CrystalDiskMark

ATTO and CrystalDiskMark (CDM) are free and easy-to-use storage benchmarking tools that SSD vendors commonly use to assign performance specifications to their products. Both of these tools give us insight into how each device handles different file sizes and at different queue depths for both sequential and random workloads.

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This is the first time we’ve benchmarked the IG5666 controller, the first faster controller from InnoGrit we’ve reviewed since the IG5236 in drives like the HP FX900 Pro. Controllers often show some nuances in ATTO and this controller is no different. Specifically, we see a drop for sequential reads at 128KiB. That’s a typical block size for testing so it's a little bit odd to see. It’s possibly due to the flash being used here, with Micron’s six-plane flash — and the typical 16KiB per page size — that there’s something going on shifting past the 96KiB per-die barrier. Once the size allows for more parallelization, the drive recovers with good performance at 2MiB and up. That’s closer to where you’d be with larger files if a PCIe 5.0 drive makes sense for you.

This is demonstrated better in CDM where you can see relatively high performance with sequential reads and writes, especially at higher queue depths. The Legend 970 Pro still shows weakness with QD1 sequential reads, but the drive redeems itself with its random reads and writes, specifically at QD1. The latency results for both are fantastic, beating all other drives in the lineup. It seems like InnoGrit optimized for that sort of workload, which is arguably bittersweet. On the one hand, 4KB performance is still very important for real-world feel. On the other hand, a PCIe 5.0 drive should always be faster with sequential workloads. If you prioritize one over the other, buy accordingly.

Sustained Write Performance and Cache Recovery

Official write specifications are only part of the performance picture. Most SSDs implement a write cache, which is a fast area of pseudo-SLC (single-bit) programmed flash that absorbs incoming data. Sustained write speeds can suffer tremendously once the workload spills outside of the cache and into the "native" TLC (three-bit) or QLC (four-bit) flash. Performance can suffer even more if the drive is forced to fold, which is the process of migrating data out of the cache in order to free up space for further incoming data.

We use Iometer to hammer the SSD with sequential writes for over 15 minutes (we ran two hours in this case) to measure both the size of the write cache and performance after the cache is saturated. We also monitor cache recovery via multiple idle rounds. This process shows the performance of the drive in various states as well as the steady state write performance.

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The 2TB Legend 970 Pro writes at over 10 GB/s for about 66 seconds in the single-bit pSLC mode, with an ample cache of up to 670GB. If this cache were converted to the native three-bit TLC mode it would be close to 2TB in size, which indicates most of this drive’s free flash is used for caching. If the drive is forced to write directly to the native TLC flash, with perhaps some copying going on in the background, it writes at around 3 GB/s with a steady state pegged at 3.17 GB/s. If the drive is further bottlenecked by having to wait for the pSLC cache to free up space, it drops down to around 2 GB/s in what could be called a folding state.

We know that this flash has the potential to be faster in the steady state, as we can see with results from the T705. Micron’s last-generation 176-Layer TLC flash is also pretty quick, indicated by the Legend 960 Max. However, cache size and write consistency are also important. The Crucial T500, for example, is notably inconsistent after caching in our testing, while the T705 utilizes a smaller but faster cache followed by relatively good performance when it runs out. This data should be taken into consideration as it can help paint a picture of how a drive will operate in edge conditions, such as with a fuller drive or sustained writes from heavier workloads.

The overall results here are pretty good, as the Legend 970 Pro gives up peak performance against the T705 to have a bigger cache and a faster baseline folding state. This is a conscious decision given the lower TLC mode performance level, and overall consistency is quite good for a cache of this size.

Power Consumption and Temperature

We use the Quarch HD Programmable Power Module to gain a deeper understanding of power characteristics. Idle power consumption is an important aspect to consider, especially if you're looking for a laptop upgrade as even the best ultrabooks can have mediocre stock storage. Desktops may be more performance-oriented with less support for power-saving features, so we show the worst-case.

Some SSDs can consume watts of power at idle while better-suited ones sip just milliwatts. Average workload power consumption and max consumption are two other aspects of power consumption but performance-per-watt, or efficiency, is more important. A drive might consume more power during any given workload, but accomplishing a task faster allows the drive to drop into an idle state more quickly, ultimately saving energy.

For temperature recording we currently poll the drive’s primary composite sensor during testing with a ~22°C ambient. Our testing is rigorous enough to heat the drive to a realistic ceiling temperature.

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The expression “yikes” comes to mind when looking at the Legend 970 Pro’s power consumption. While we’re used to PCIe 5.0 drives like the T705 being somewhat inefficient, the Legend 970 Pro brings us back to the 3.0 days with unoptimized technologies. Newer flash, newer DRAM, and newer controllers push toward being more efficient, and not just from finishing workloads faster. Unfortunately, the IG5666 controller appears to be more about brute force and less about innovation.

Phison E26-based drives like the T705 have always had problems with desktop idle power draw, going back to the original E26 prototype. This is not as big a problem as it seems because, for one, a drive like this is intended to be used in a high-performance machine and, secondly, we’re not testing under ideal conditions. Drives like this should never make their way into a laptop either. That goes double for the Legend 970 Pro’s IG5666, as well, since it also has a horribly high idle power draw. This has nothing to do with the fan and, given the high peak draw, appears to be an optimization issue.

We’re not clear on the architecture but we did speculate above in comparison to the IG5220/IG5221 — although the IG5236 might be a better comparison, despite having half the bus rate. If we look at it from that angle, we suspect the IG5666 has twice the cores and has them running at higher clock speeds as well. It’s rated for at most double the performance, so some quick math reveals that having an efficiency level below the last gen makes sense. In the grand scheme of things, say by looking at average power draw, this is not a huge difference for any serious desktop. Bare drives with this hardware might need extra cooling attention, though.

Luckily, that’s not an issue for the Legend 970 Pro, as it comes clad with a heatsink and an M.2-powered fan. In our testing it reached about 64°C, which is well below throttling temperature. This means that, realistically and even with an unplugged fan, this drive will operate mostly like any other.

Test Bench and Testing Notes

We use an Alder Lake platform with most background applications such as indexing, Windows updates, and anti-virus disabled in the OS to reduce run-to-run variability. Each SSD is prefilled to 50% capacity and tested as a secondary device. Unless noted, we use active cooling for all SSDs.

Adata Legend 970 Pro Bottom Line

The Adata Legend 970 Pro is the first SSD of its class: a full-fledged PCIe 5.0 drive that doesn't use the Phison E26 controller. SMI has been slow to arrive on the scene with its own solution, but in the meantime this drive delivers the InnoGrit IG5666. The flash itself isn’t any different than what we've already seen elsewhere, so we can focus purely on the controller platform.

The result is that, while we have previously held its high idle power consumption against Phison’s E26, the IG5666 is even worse. To add onto that, power efficiency as a whole is worse, which is to be expected to some degree based on our knowledge of the hardware. The drive is no slouch in raw performance, although existing drives like the Crucial T705 or Sabrent Rocket 5 are certainly superior even if the real-world difference may not be massive.

The Legend 970 Pro is not without its bright spots, though. It comes with a decent heatsink that includes a built-in fan for active cooling. This fan does not require an extra connector and can also be disconnected. This is an improvement over the Phison E26’s reference design. Unfortunately, the fan — like other fans of its ilk — can get quite loud if the SSD decides to ramp up fan speeds.

Adata also has relatively good software support that, while not a critical thing whatsoever, could be useful for new builders. The drive also still manages some good numbers, particularly with random read latency for 4KB at QD1. As a result, it will feel quite responsive in everyday use and has extra horsepower over last-generation drives.

The Legend 970 Pro has a shot if it’s priced right. Put simply, it needs to come into the market priced below the current fastest PCIe 5.0 SSDs to make sense. It could be a convenient solution if you want to pick up a very fast 2TB drive to drop into your system without worrying about custom cooling. The poor power efficiency isn’t as big a deal as it appears as a watt here or there in an enthusiast system is barely noticeable.

Still, there are several good drives using Phison’s hardware with better all-around performance, and if you’re spending this much on a drive you probably aren't concerned about saving a little money on your PCIe 5.0 SSD by going with an alternative like controller. If you want the best, fastest SSD around, nothing has changed: Crucial T705 still reigns at the top. But having more options isn’t a bad thing, and the Legend 970 Pro is far from being a slow drive.

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