In 2022, Intel quietly buried the fastest storage medium anyone had ever shipped. Optane, built on 3D XPoint memory, was a drive technology that laughed at NAND when it came to latency and endurance — and it was cancelled, not because it was slow, but because it never got cheap. Four years later, the fastest consumer SSDs on the market still lose to a discontinued 2021 drive in the metric that matters most for databases: how long a single small read takes. This post compares the last great Optane drive, the P5800X, against the modern NAND SSDs that were supposed to replace it.
What 3D XPoint Actually Was
NAND flash stores bits by trapping electrons in floating gates. It is cheap, dense, and stubborn: you can only write to an empty page, and you can only empty pages by erasing them in large blocks. That asymmetry is why every NAND SSD carries a controller that juggles garbage collection, wear leveling, and an SLC write cache — and why write latency varies wildly depending on what the drive is doing in the background.
3D XPoint was a completely different memory. It stored bits by changing the physical state of a material inside a selector cell, and it was byte-addressable: you could overwrite a single byte without erasing anything. No read-disturb, no erase-before-write, no garbage collection tax. The result was memory that was roughly a thousand times slower than DRAM but a hundred times faster to answer than NAND — and essentially immune to write wear by comparison.
Intel and Micron developed it together, then split in 2018. Micron walked away from XPoint entirely and sold its Lehi fab to Texas Instruments in 2021. Intel pressed on with second-generation media and shipped the Optane SSD P5800X — arguably the fastest SSD ever made, and the last one that would use the technology.
Latency: The Metric NAND Never Fixed
Between 2013 and now, NAND SSD sequential bandwidth improved roughly fivefold — SATA’s 550 MB/s became PCIe 5.0’s 14,000 MB/s. Random read latency at low queue depth barely moved. A good SATA drive answered a 4K random read in around 100 microseconds a decade ago; a modern PCIe 4.0 flagship answers in 70 to 90 microseconds. The interface got faster; the media did not.
The P5800X, measured at low queue depth, answers 4K random reads in roughly 18 microseconds, and does it whether the drive is empty, 90% full, or mid-write. Its 512-byte random read latency is about 3.5 microseconds — Intel’s own figures put it up to 95% below a comparable NVMe NAND drive under load. That consistency is the part reviewers struggled to convey in a bar chart: a NAND SSD at QD32 looks impressive, but at QD1 under mixed write load, its latency distribution grows a long tail from cache flushing and garbage collection. The Optane drive’s tail is nearly flat.
Endurance: Not Even Close
Endurance is rated in drive writes per day (DWPD) — how many times you can overwrite the entire drive daily for the five-year warranty period. Here the gap is absurd:
| Drive class | DWPD |
|---|---|
| Consumer QLC | 0.1 |
| Consumer TLC | 0.2 – 0.35 |
| Enterprise read-intensive | 1 |
| Enterprise mixed-use | 3 |
| Enterprise write-intensive | 10 |
| Intel Optane P5800X | 100 |
A P5800X is rated to take a full-drive overwrite every fifteen minutes, for five years. NAND cannot get there — erasing blocks is what wears it out, and XPoint has no erase. This is why Optane drives found homes as ZFS SLOG devices, database write-ahead logs, and any workload that hammers the same few gigabytes forever.
Where Modern NAND Wins
To be fair to NAND: it wins on almost everything else. The P5800X tops out around 7.2 GB/s sequential read and 6.2 GB/s sequential write on PCIe 4.0. A current-gen PCIe 5.0 drive doubles that. Streaming a multi-terabyte dataset, loading checkpoints, serving video — sequential-throughput workloads — NAND is far ahead, and it costs a fraction per gigabyte. Optane topped out at 3.2 TB per drive; you can buy 8 TB NAND in the same M.2 slot. Capacity per wafer is where XPoint lost the economics permanently: the process never scaled the way NAND’s did, and Intel never got cost per bit anywhere near competitive.
The industry’s answer to Optane’s death was underwhelming. Kioxia’s XL-Flash and Samsung’s Z-NAND are low-latency SLC-adjacent NAND flavors that narrow the gap somewhat, but they remain niche enterprise products. CXL memory pooling aims at the capacity tier Optane’s persistent-memory DIMMs occupied. Neither matches what the media actually did.
Measuring Your Own Drive
If you want to see the latency gap yourself, the tool is fio. The measurement that separates Optane from NAND is single-queue, single-job 4K random read with a high fill level — no queue depth to hide behind:
# QD1 4K random read latency against a test file (safe, uses a file image)
fio --name=qd1-lat --filename=/mnt/nvme/fiotest.bin --size=8G \
--rw=randread --bs=4k --iodepth=1 --numjobs=1 \
--direct=1 --runtime=60 --time_based \
--output-format=json | jq '.jobs[0].read.lat_ns.mean / 1000'
# Compare against QD32 to see the gap Optane never had
fio --name=qd32-iops --filename=/mnt/nvme/fiotest.bin --size=8G \
--rw=randread --bs=4k --iodepth=32 --numjobs=1 \
--direct=1 --runtime=60 --time_based --output-format=jsonRun it against a modern TLC drive and a P5800X and the pattern repeats: the NAND drive closes the gap at high queue depth and loses by a factor of four to five at QD1, with far worse tail latency under concurrent writes. The QD32 number is what marketing quotes; the QD1 number is what your database feels.
Should You Hunt One Down?
Here is the twist: discontinued does not mean unavailable. P5800X drives have flooded the secondary market as data centers retire them, and prices have collapsed from roughly $1,900 at launch to a few hundred dollars for the 400 GB model. For a specific and real set of uses, they remain the best tool available:
- ZFS SLOG devices, where a drive that survives sync-write storms is exactly the spec
- Database WAL and redo log volumes for Postgres or MySQL on write-heavy hosts
- Kafka or NATS journal disks where fsync latency is the throughput limit
- Any latency-sensitive service where the long tail matters more than capacity
Just verify the drive is genuine (counterfeits exist), check your platform supports PCIe 4.0 U.2 or add-in-card form factors, and accept that every drive you can buy is used inventory with a finite end.
The Takeaway
The Optane story is not a story about a failed product — it is a story about a product whose economics failed while its engineering won. Modern SSDs are magnificent at moving big streams of data and remain an order of magnitude behind a dead technology at answering one small question quickly. Until NAND media fundamentally changes, the fastest answer to a 4K random read in most labs is a drive that is no longer made, powering workloads its own manufacturer abandoned.