The Intel Optane SSD DC P4800X (375GB) Review: Testing 3D XPoint Performance
by Billy Tallis on April 20, 2017 12:00 PM ESTChecking Intel's Numbers
The product brief for the Optane SSD DC P4800X provides a limited set of performance specifications, entirely omitting any standards for sequential throughput. Some latency and throughput targets are provided for 4kB random reads, writes, and a 70/30 mix of reads and writes.
This section has our results for how the Optane SSD measures up to Intel's advertised specifications and how the flash SSDs fare on the same tests. The rest of this review provides deeper analysis of how these drives perform across a range of queue depths, transfer sizes, and read/write mixes.
| 4kB Random Read at a Queue Depth of 1 (QD1) | |||||||
| Drive | Throughput | Latency (µs) | |||||
| MB/s | IOPS | Mean | Median | 99th | 99.999th | ||
| Intel Optane SSD DC P4800X 375GB | 413.0 | 108.3k | 8.9 | 9 | 10 | 37 | |
| Intel SSD DC P3700 800GB | 48.7 | 12.8k | 77.9 | 76 | 96 | 2768 | |
| Micron 9100 MAX 2.4TB | 35.3 | 9.2k | 107.7 | 104 | 117 | 306 | |
Intel's queue depth 1 specifications are expressed in terms of latency, and at a throughput specification at QD1 would be redundant. Intel specifies a "typical" latency of less than 10µs, and most QD1 random reads on the Optane SSD take 8 or 9µs; even the 99th percentile latency is still 10µs.
The 99.999th percentile target is less than 60µs, which the Optane SSD beats by a wide margin. Overall, the Optane SSD passes with ease. The flash SSDs are 8-12x slower on average, and the 99.999th percentile latency of the Intel P3700 is far worse, at around 75x slower.
| 4kB Random Read at a Queue Depth of 16 (QD16) | |||||||
| Drive | Throughput | Latency (µs) | |||||
| MB/s | IOPS | Mean | Median | 99th | 99.999th | ||
| Intel Optane SSD DC P4800X 375GB | 2231.0 | 584.8k | 25.5 | 25 | 41 | 81 | |
| Intel SSD DC P3700 800GB | 637.9 | 167.2k | 93.9 | 91 | 163 | 2320 | |
| Micron 9100 MAX 2.4TB | 517.5 | 135.7k | 116.2 | 114 | 205 | 1560 | |
Intel's QD16 random read result is 584.8k IOPS for throughput, which is above the official specification of 550k IOPS by a few percent. The 99.999th percentile latency scores 81µs, significantly under the target of less than 150µs. The flash SSDs are 3-5x slower on most metrics, but 20-30 times slower at the 99.999th percentile for latency.
| 4kB Random Write at a Queue Depth of 1 (QD1) | |||||||
| Drive | Throughput | Latency (µs) | |||||
| MB/s | IOPS | Mean | Median | 99th | 99.999th | ||
| Intel Optane SSD DC P4800X 375GB | 360.6 | 94.5k | 8.9 | 9 | 10 | 64 | |
| Intel SSD DC P3700 800GB | 350.6 | 91.9k | 9.2 | 9 | 18 | 81 | |
| Micron 9100 MAX 2.4TB | 160.9 | 42.2k | 22.2 | 22 | 24 | 76 | |
In the specifications, the QD1 random write specifications are 10µs on latency, while the 99.999th percentile for latency is relaxed from 60µs to 100µs. In our results, the QD1 random write throughput (360.6 MB/s) of the Optane SSD is a bit lower than the QD1 random read throughput (413.0 MB/s), but the latency is roughly the same (8.9µs mean, 10µs on 99th).
However it is worth noting that the Optane SSD only manages a passing score when the application uses asynchronous I/O APIs. Using simple synchronous write() system calls pushes the average latency up to 11-12µs.
Also, due to the capacitor-backed DRAM caches, the flash SSDs also handle QD1 random writes very well. The Intel P3700 also manages to keep latency mostly below 10µs, and all three drives have 99.999th percentile latency below Intel's 100µs standard for the Optane SSD.
| 4kB Random Write at a Queue Depth of 16 (QD16) | |||||||
| Drive | Throughput | Latency (µs) | |||||
| MB/s | IOPS | Mean | Median | 99th | 99.999th | ||
| Intel Optane SSD DC P4800X 375GB | 2122.5 | 556.4 | 27.0 | 23 | 65 | 147 | |
| Intel SSD DC P3700 800GB | 446.3 | 117.0 | 134.8 | 43 | 1336 | 9536 | |
| Micron 9100 MAX 2.4TB | 1144.4 | 300.0 | 51.6 | 34 | 620 | 3504 | |
The Optane SSD DC P4800X is specified for 500k random write IOPS using four threads to provide a total queue depth of 16. In our tests, the Optane SSD scored 556.4k IOPs, exceeding the specification by more than 11%. This equates to a random write throughput of more than 2GB/s.
The flash SSDs are more dependent on the parallelism benefits of higher capacities, and as a result can be slow at the same capacity. Hence in this case the 2.4TB Micron 9100 fares much better than the 800GB Intel P3700. The Micron 9100 hits its own specification right on the nose with 300k IOPS and the Intel P3700 comfortably exceeds its own 90k IOPS specification, although remaining the slowest of the three by far. The Optane SSD stays well below its 200µs limit for 99.999th percentile latency by scoring 147µs, while the flash SSDs have outliers of several milliseconds. Even at the 99th percentile the flash SSDs are 10-20x slower than Optane.
| 4kB Random Mixed 70/30 Read/Write Queue Depth 16 | |||||||
| Drive | Throughput | Latency (µs) | |||||
| MB/s | IOPS | Mean | Median | 99th | 99.999th | ||
| Intel Optane SSD DC P4800X 375GB | 1929.7 | 505.9 | 29.7 | 28 | 65 | 107 | |
| Intel SSD DC P3700 800GB | 519.9 | 136.3 | 115.5 | 79 | 1672 | 5536 | |
| Micron 9100 MAX 2.4TB | 518.0 | 135.8 | 116.0 | 105 | 1112 | 3152 | |
On a 70/30 read/write mix, the Optane SSD DC P4800X scores 505.9k IOPS, which beats the specification of 500k IOPS by 1%. Both of the flash SSDs deliver roughly the same throughput, a little over a quarter of the speed of the Optane SSD. Intel doesn't provide a latency specification for this workload, but the measurements unsurprisingly fall in between the random read and random write results. While low-end consumer SSDs sometimes perform dramatically worse on mixed workloads than on pure read or write workloads, none of these drives have that problem due to their market positioning and capabilities therein.
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melgross - Tuesday, April 25, 2017 - link
You obviously have some ax to grind. You do seem bitter about something.The first SSDs weren't much better than many HHD's in random R/W. Give it a break!
XabanakFanatik - Thursday, April 20, 2017 - link
I know that this drive isn't targeted for consumers at all, but I'm really interested in how it performs in consumer level workloads as an example of what a full Optane SSD is capable of. Any chance we can get a part 2 with the consumer drive tests and have it compared to the fastest consumer NVM-e drives? Even just a partial test suite for a sampler of how it compares would be great.Drumsticks - Thursday, April 20, 2017 - link
I imagine it will be insane - the drive saturates its throughput at <QD6, meaning most consumer workloads. It'll obviously be a while before its affordable from a consumer perspective, but I suspect the consumer prices will be a lot lower without the enterprise class requirements thrown in.This drive looks incredibly good. 2-4x more than enterprise SSDs for pretty similar sequential throughput - BUT at insanely lower queue depths, which is a big benefit. At those QDs, it's easily justifying its price in throughput. Throw on top of that a 99.999th% latency that is often better than their 99th% latency, and 3D Xpoint has a very bright future ahead of it. It might be gen 1 tech, but it's already justified its existence for an entire class of workloads.
superkev72 - Thursday, April 20, 2017 - link
Those are some very impressive numbers for a gen1 storage device. Basically better than an SSD in almost every way except of course price. I'm interested in seeing what Micron does with QuantX as it should have the same characteristics but potentially more accessible.DrunkenDonkey - Thursday, April 20, 2017 - link
Well finally! I was waiting for this test ever since I heard about the technology. This is enterprise drive, yeah, but it is the showcase for the technology and it shows what we can expect for consumer drive - 8-10x current SSD speeds for desktop usage (that is 98% 4-8k RR, QD=1). That blows out of the water everything in the market. Actually this technology shines exactly at radon joe's PC, while SSDs shine only in enterprise market (QD=16+). Can't wait!Meteor2 - Thursday, April 20, 2017 - link
But don't we say SATA3 is good enough and we don't really need (for consumer use) NVMe? So what's the real benefit of something faster?DrunkenDonkey - Thursday, April 20, 2017 - link
All you want (from desktop user perspective) is low latency at low queue depth (1). NVME helps with that regard, tho not by a lot. Equal drives, one on sata, one on nvme will make the nvme a bit more agile resulting in more performance for you. So far no current ssd is ever close to saturate the sata3 bus in desktop use, this one, however, is scratching it. Sure, it will be years till we get affordable consumer drives from that tech, but it is pretty much the same step forward than going from hdd to ssd - first ssds were in the range of 20ish mb per second, while hdds - about 1.5 in these circumstances. Here we are talking a jump from 50 to close to 400+. Moar power! :)serendip - Thursday, April 20, 2017 - link
Imagine having long battery life and instant hibernation - at 400 mbps, waking up from hibernation and reloading memory contents would take a few seconds. Then again, constantly writing a huge page file to XPoint wouldn't be good for longevity and hibernation doesn't allow for background processes to run while asleep. I'm thinking of potential usage for XPoint on phones and tablets, can't seem to find any.ddriver - Friday, April 21, 2017 - link
Yeah, also imagine your system working 10 times slower, because it uses hypetane instead of ram.And not only that, but you also have to replace that memory every 6 months or so, because working memory is much more write intensive, and this thing's endurance is barely twice that of MLC flash.
It is well worth the benefit of instant resume, because if enterprise systems are known for something, that is frequently hibernating and resuming.
tuxRoller - Friday, April 21, 2017 - link
They didn't say replace the ram with xpoint.It's a really good idea since xpoint has faster media access times so even when it's a smaller amount it should still be quite a bit faster than nand.