The Intel Optane SSD DC P4800X (375GB) Review: Testing 3D XPoint Performanceby Billy Tallis on April 20, 2017 12:00 PM EST
Checking 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)|
|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)|
|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)|
|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)|
|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|
|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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ddriver - Friday, April 21, 2017 - linkSo if you populate the dimm slots with hypetane, where does the dram go?
kfishy - Friday, April 21, 2017 - linkYou can have a hybrid memory subsystem, the current topology of CACHE-DRAM-SSD/HDD is not the only way to go.
tuxRoller - Friday, April 21, 2017 - linkWhy are you mentioning dimms?
Are you just posting random responses?
Neither of your posts in this thread actually addressed anything that the posters were discussing.
Kakti - Saturday, April 22, 2017 - linkHave you been living in a cave the past five years? SATA 3.0 has been the limiting factor for SSDs for a while now - all max out around 450MB/sec.
Now there are plenty of SSD that connect via PCIe instead of SATA and are able to pull several gigabytes/sec. Examples include Samsung 960 Pro/Evo, 950 Pro, OCZ RD400, etc. SATA has ben the bottleneck for a while and now that we have NVMe, we're seeing what NAND can really do with m.2 or pci-e connections
cfenton - Thursday, April 27, 2017 - linkThat speed is only for high queue depth workloads. Even the 960 Pro only does about 137mb/s average in random reads over QD1, QD2, and QD4. The QD1 numbers are something like 34mb/s. Those numbers are far below the SATA spec. Almost all consumer tasks are low queue depth.
With this drive, you get about 400mb/s even at QD1, and something like 1.3gb/s at QD4.
CajunArson - Thursday, April 20, 2017 - linkA very very sweet piece of technology assuming you have the right workloads to take advantage of what it can offer. Obviously it's not going to do much for a consumer grade desktop, at least not in this form factor & price.
It's pretty clear that in at least some of those tests the PCIe interface is doing some bottlenecking too. It will be interesting to see Optane integrated into memory DIMMs where that is no longer an issue.
tarqsharq - Thursday, April 20, 2017 - linkI can imagine this on a heavily trafficked database server would be insanely effective.
ddriver - Friday, April 21, 2017 - linkNot anywhere nearly as fast as an in-memory database.
Chaitanya - Thursday, April 20, 2017 - linkLike most recent Intel products: overpriced, and overhyped.
vortmax2 - Thursday, April 20, 2017 - linkI don't agree. For Gen1, I'd say it's about right on. It seems that consumer storage advancements are accelerating (SSD, NAND, now this inside a decade). I for one am happy to see a part of Intel (albeit a joint partnership) pressing ahead and releasing revolutionary tech - soon to me enjoyed by consumers.