Reviews

SanDisk Ultra 3D SSD 500GB review: A respectable mid-range SSD, but not the best

This SSD uses SLC caching trickery to keep write speeds high, but don’t expect industry-leading performance

Pros

High write speeds
Good durability

Cons

Inconsistent in everyday use

No matter how ingenious the manufacturers’ R&D departments might be, a SATA SSD can only go so fast: throughput limits mean that it’s only going to get harder for a SATA-based SSD to innovate. The best drives in the business, particularly the Samsung 860 Evo, are already getting close to the maximum speeds allowed by the SATA3 interface.

SanDisk Ultra 3D SSD 500GB review: What you need to know

Today’s SSDs need ways to stand out, and one of SanDisk’s favoured tools for doing so has been its nCache 2.0 system. It works very similarly to the tiered SLC/TLC memory setup of the WD Black, which is unsurprising considering how many SanDisk parts are inside that drive: all data writes are sent through a layer of fast SLC NAND before data is moved to the slower TLC NAND, with the aim of improving performance while keeping prices within expectations for a SATA SSD. SLC is expensive, so SanDisk uses just enough to speed things up without relying on it completely.

The Ultra 3D SSD is a good showcase of nCache 2.0 in action, and that goes for demonstrating its limitations as well as showing off its benefits. Before we get to benchmark results, let’s take a look at the key specs: the Ultra 3D SSD is available in 250GB, 500GB (the model we’re reviewing here), 1TB and 2TB varieties, all of which, with the exception of the 250GB model, are quoted as having a maximum read speed of 560MB/s and a maximum write speed of 530MB/s. Opt for the smallest capacity, and these drop to 550MB/s read and 525MB/s write.

That’s still very ambitious, as even the 860 Evo only claims to reach 550MB/s read and 520MB/s write. The Ultra 3D SSD also comes in very slightly cheaper than its Samsung rival: we calculated its cost per gigabyte as 24.3p for the 250GB model, 20.8p for the 500GB model, 24p for the 1TB model and 18.7p for the 2TB model. You might only end up saving a pound or two on the 860 Evo equivalent, as SanDisk’s SSD is still near the higher end of the SATA-based market, but still.

SanDisk Ultra 3D SSD 500GB review: Performance

Testing with CrystalDisk Mark, it initially looks as though the Ultra 3D SSD will go blow-for-blow on performance as well. In the standard sequential test, it scored an immense read speed of 563MB/s and an equally impressive 535MB/s write speed. Besides slightly exceeding SanDisk’s own advertised speeds, these also edge ahead of the 860 Evo, if only by about 1MB/s in the read test and 3MB/s in the write test.

However, when subjected to more gruelling tasks, the Ultra 3D SSD doesn’t hold up nearly as well. Switching to CrystalDiskMark’s 4K file test saw read speeds drop to an underwhelming 254.2MB/s, and write speeds to 237.6MB/s. By contrast, the 860 Evo scored 400.8MB/s and 364MB/s respectively – it’s not even a close fight.

Things were a bit closer in our own file transfer tests, which replicate real-life usage more accurately than synthetic benchmarks, but the Ultra 3D SSD still came out behind, sometimes by more than 100MB/s. In the huge file test, for instance, the SanDisk drive averaged a read speed of 425.91MB/s and a write speed of 487MB/s, which is fine but not on par with the best of the best.

In the large file test, the Ultra 3D SSD to its credit didn’t slow down too much, considering it had a lot more files to deal with. We measured an average read speed of 416.97MB/s and an average write speed of 414.13MB/s, which again is decent rather than spectacular.

Lastly, we ran our most demanding small files test. It was here where nCache 2.0 was most visibly at work. Because it boosts write speeds but doesn’t work so well when reading, the drive recorded a high average write speed of 409.47MB/s but a greatly diminished 240.79MB/s read. The former still wasn’t up to the 860 Evo’s outstanding 503.7MB/s average write, but we’ve seen much worse.

On that note, the Ultra 3D SSD shouldn’t be entirely discounted for falling short of its nemesis. All things considered, it’s still a pretty fast SSD, and even if it’s not the outright fastest around, it comfortably outpaces the more expensive Kingston UV500.

Durability is another feather in the Ultra 3D’s cap. The 500GB model is rated at 200 terabytes written (TBW), enough for many years of heavy use, and this climbs quickly if you can afford the larger capacities: the 1TB model gets 400TBW, while the 2TB model gets a hefty 500TBW. Even the basic 250GB model will last plenty long enough, being rated at 100TBW.

SanDisk Ultra 3D SSD 500GB review: Verdict

You should still buy the 860 Evo, but the Ultra 3D SSD is hard to actively dislike. nCache 2.0 ensures high write speeds in trying conditions, and in certain, specific conditions it can reach exceptional speeds – it’s just that Samsung’s drive is a lot better at staying fast during everyday use.