Silicon Power PCIe Gen 4×4 UD90 1TB NVMe SSD Review – Excellent Value

A drive that performs better than it has to

SSDs, even of the Gen4 NVMe variety, have been getting very affordable in recent months. Who knows if that will change anytime soon, but it is a refreshing trend in the era of impossibly expensive graphics cards, rising motherboard costs, DDR5, and so on.

A newer option on the market is the UD90, a PCIe Gen 4 NVMe SSD from Silicon Power (SP), and it undercuts the price of just about everything out there right now in the 1TB capacity – which happens to be the version in for review. How inexpensive is it? As I write this the drive is on sale for just $61.99 on Amazon.

Don’t be fooled by the low-end price, however, as this drive offers solid performance. Sure, the top sequential speeds advertised aren’t going to blow you away – though 5000 MB/s reads and 4800 MB/s writes are nothing to scoff at. No, it is the consistent performance characteristics of the drive that impressed us, as you will find out shortly.

The PCIe Gen 4×4 UD90

While very much the unassuming SSD when you pull it from the package, the chips beneath the foil label on this single-sided board are quite interesting. Silicon Power is using a Phison E21 controller (PS5021-E21T, PDF), with Micron 176-Layer 3D TLC NAND – no QLC here (credit TechPowerUp for the chip info).

The Phison controller is DRAM-less, but Silicon Power is using TLC, rather than QLC, NAND – along with the expected SLC caching. Speaking of NAND, Silicon Power offers this UD90 in capacities of 250GB, 500GB, 1TB , 2TB, and 4TB, though only the 1TB and 2TB were listed on Amazon when I checked.

Features of the UD90 (quoting Silicon Power):

• PCIe Gen 4×4 interface with read speeds up to 5,000MB/s and write speeds up to 4,800MB/s
• Supports NVMe 1.4 and Host Memory Buffer (HMB) for higher performance and lower latency
• 3D NAND technology allows for dense storage in a compact design
• Available in a range of storage capacity options: 250GB, 500GB, 1TB , 2TB and 4TB
• Supports low density parity check (LDPC) coding to ensure accuracy of data transmission and reliability of data access
• Supports SLC Caching to improve sequential read/write and random read/write performance
• Supports RAID to protect data in the case of a drive failure
• Built-in E2E data protection for enhanced data transfer integrity
• Small form factor M.2 2280 (80mm) allows for easy installation in laptops, small form factor PC systems, and some ultrabooks
• Free download of SP ToolBox to easily obtain disk information such as self-monitoring analysis report, extent of consumption and SSD diagnostics

Performance Testing

Let’s get right into this, first looking at performance with an empty drive vs. a drive filled to 50% capacity:

CrystalDiskMark ‘Peak Performance’ preset, empty drive (left) vs. half-full drive (right)

There isn’t much of a difference, is there? But a synthetic “peak performance” test is a best-case scenario, so let’s compare PCMark 10 Full System Drive benchmarks:

In the Full System Drive benchmark with an empty drive, the UD90 managed average bandwidth of 391.53 MB/s, with average access time of 70 μs (microseconds). Filled to 50% capacity, the performance dropped a bit to 332.64 MB/s average bandwidth and 83 μs average access time. As end-users tend not to use empty drives, all benchmarks to follow show results with the drive filled to the same 50% capacity.

But first, a word on the comparison charts to follow. I have not tested “low-end” PCIe Gen4 drives to this point, and putting this (currently) $62 drive up against the likes of a Samsung 990 PRO seems ridiculous. At some point there will be a more reasonable roundup of affordable drives, so please ignore the massive pricing gulf for now.

First, let’s take a look at random 4K reads and writes using CrystalDiskMark, at queue depths of 1, 2, 4, and 8 (all single-thread):

These charts were arranged by QD8 results, which actually places the UD90 ahead of the Solidigm P44 Pro in the 4K random read chart – but it was slower at the lower queue depths in the 4K random read benchmarks. The random write benchmarks are more interesting.

At a queue depth of one, this Silicon Power drive hit a high of 321.91 MB/s, placing up near a Samsung 990 PRO 2TB (326.24 MB/s), and faster than the 980 PRO 2TB (287.36 MB/s). The and SK Hynix / Solidigm drives do quite a bit better at low queue-depth 4K random write operations, but I was quite impressed by this little drive down at QD1.

The UD90 didn’t scale upward as much as the rest of the drives at higher queue-depths, but 4K random write was an overall very respectable showing – particularly for a drive that costs so much less than than the rest of this group.

For your own reference, here are screenshots of the CrystalDiskMark tests at each queue depth:

The sequential numbers aren’t going to do anything but occupy the bottom slot on any of my charts given the competition, but here they are anyway:

And now for a further exercise in how NOT to review a budget drive: more comparisons with high-end hardware:

Well, there’s nothing exciting to report about a result like this. This drive is not suited to a comparison chart like this one, and I need to test some QLC Gen4 drives to see how they stack up in the budget segment.

The Quick System Drive Benchmark result is provided for your reference, and my pain:

Other than being able to comment “wow, the 980 PRO 2TB just isn’t all that fast, is it?” I don’t see the point in continuing to present these charts.

Final Thoughts

This conclusion is a very simple one. I’ll just list some facts:

• Silicon Power has produced a 1TB PCIe 4.0 x4 NVMe SSD that sells for as little as $62.
• It was designed around a Phison E21 controller, and uses 3D TLC NAND.
• It offers strong 4K random performance at low-queue depths, and respectable overall speed.
• Did I mention the $62 price?

I’ll reiterate a key point here: all benchmarking was conducted with the drive filled to 50% capacity (other than the empty drive comparisons). This “steady state” condition does lower performance, but I was impressed by how well this inexpensive drive fared under unfavorable conditions.

In short, the SP UD90 is an excellent value, offering performance where it counts – even if the top speeds aren’t flashy.