Adata Legend 970 Pro SSD review: More pretender than contender

Adata has finally delivered the first real PCIe 5.0 SSD that doesn't use a Phison E26 controller. Curiously, the new model gets the Legend 970 Pro name, taking over from the earlier Legend 970. What differences does one word make? Quite a lot, as the new variant can read up to 4 GB/s faster under ideal conditions. As we know by now, though, the specs on the box don’t always match reality.

Does Adata have a winner on its hands this time, and can the Legend 970 Pro join the ranks of the best SSDs? We can at least applaud the cooling, as it features a capable heatsink paired with a fan that’s powered through the M.2 slot — no annoying external connector required! That alone helps it stand out, but the Legend 970 Pro also brings a new controller to the table with the InnoGrit IG5666. Previous high-end PCIe 5.0 drives we’ve reviewed, like the Sabrent Rocket 5, rely on Phison’s E26 instead.

Performance at this level doesn’t come cheap. For that matter, neither is it coming in a laptop-capable package. These high-end SSDs pull a lot of power and require cooling of some sort to operate normally. For those hoping the Legend 970 Pro or IG5666 could help break this trend, the unfortunate news is that you’ll be waiting a bit longer. More efficient controllers and flash are on the way, but for now a drive like this remains a strictly enthusiast part. 

Adata Legend 970 Pro Specifications

The Adata Legend 970 Pro is available in the most popular capacities: 1TB, 2TB, and 4TB. You won’t see a lot of PCIe 5.0 drives with smaller capacities than this because you need a minimum number of flash dies to reach decent performance levels. This is less true for budget, four-channel options that are on the way, but flash is inevitably getting denser so over time this will continue to be the trend. The Legend 970 Pro can’t even hit its peak sequential read performance at 1TB — only 13,000 MB/s rather than 14,000 MB/s — and sequential write performance at 5,800 MB/s is far below the 4TB’s claimed 11,000 MB/s. We would therefore recommend starting at 2TB if you are buying a drive of this caliber.

The drive can reach up to an impressive 1,800K / 1,300K IOPS for random reads and writes, which seems to be a relative maximum for now. There’s the potential for more in the future with different flash or an optimized controller architecture. Adata backs this drive with a 5-year warranty and 740TB of writes per TB capacity, which is slightly more than typical but not too far beyond the norm. We don’t have pricing data available yet, although the drive needs to be competitive — in this case, that means cost less — than something like the Crucial T705. 

Adata Legend 970 Pro Software and Accessories

Adata offers three software packages for download on its website for Adata storage product purchasers: the Adata SSD Toolbox, Adata SSD Migration Tool, and Adata Backup ToGo. The first is your standard SSD toolbox with drive information, basic diagnostics, utilities for secure erasing and firmware updates, benchmarking, SSD optimization or TRIM, and oddly a drive clone feature. The second piece of software allows you to clone, backup, and recover data from your SSD. The final download lets you make regular backups for your data, and supports both Windows and Android platforms.

It's more than you get from a lot of generic brand SSDs, and the potential for firmware updates is high given the new IG5666 controller. We've been hearing about other non-Phison PCIe 5.0 drives for at least two years now, so it's nice to finally see a retail product. However, being first means there's a much greater chance that future firmware updates will be needed as turning progresses over time. 

Adata Legend 970 Pro: A Closer Look

Image 1 of 4

The Adata Legend 970 Pro comes adorned with a double-sided heatsink with an integrated fan. This is a necessary apparatus as the drive produces quite a bit of heat. The potential for a bare drive with this hardware exists, but as with other high-end PCIe 5.0 drives — those based on Phison’s E26 controller rather than the InnoGrit IG5666 that we have here — you will need to provide a heatsink. Active cooling is generally not required but can be useful in some environments.

The included fan plugs into a header on the PCB but can be externally-powered if necessary. E26-based drives, on the other hand, generally require an external power source for the fans to operate. Based on further analysis of PCB components, it appears that the fan is using 5V power stepped up from the M.2 3.3V supply. Personally, we find it nice not to deal with extra external cables, but you can still unplug the fan if you want to eliminate any noise (which became quite audible at times during testing).

Image 1 of 2

We can’t really talk about this new controller, the InnoGrit IG5666, without mentioning the competition. Phison’s E26, which peaks in a drive like the Crucial T705, is by far the most common PCIe 5.0 SSD controller on the market. We’re happy to see some competition, but that means we have to explore the differences between these two controllers.

Both controllers are eight-channel, 12nm, 2400 MT/s designs. This means they can access flash across eight channels at once for more bandwidth, are not super efficient as 12nm needs a lot of power to drive high-performance flash, and that they are designed for specific flash. In the future, we will see 6nm/7nm controllers that can handle flash speeds up to 3600 MT/s or even 4800 MT/s with as few as four channels. These two controllers also use DRAM, which can improve performance and endurance but also pulls more power. Briefly, then: These drives have the potential to pull a lot of power.

As for architecture, it’s not yet clear what InnoGrit has under the hood with the IG5666. We suspect that it borrows from enterprise designs, which could be RISC-V or simply Cortex-R5. The former isn’t too crazy as Phison’s E26 uses a custom RISC-V for its companion cores. If we had to guess, though, the IG5666 probably uses two quad-core R5s like the IG5668. While such cores can share duties equally, it’s not uncommon to have some specialization. So you would have cores to handle writes, reads, NAND management, and cache management. The takeaway could simply be that this design will likely be power-hungry, even more so than the E26.

Compare this to our findings from the excellent budget drives built on InnoGrit’s IG5220, such as the Patriot P400 or the HP FX900. The latter in particular was done right, with excellent power efficiency at the time. Now take those three cores and go to eight, and raise the clock rates as well. Yes, the Legend 970 Pro’s IG5666 provides much higher performance, but it fundamentally has the same technology — on the same node, the same 2400 MT/s flash support, and even the same LDPC generation for error correction. You can even add DRAM if you count the IG5221. We’ll compare this drive with an IG5236 on the next page, but it doesn’t take much imagination to expect power issues with this level of scaling. 

MORE: Best SSDs

MORE: How We Test HDDs And SSDs

MORE: All SSD Content