1450k IOPS 4K-R
1200k IOPS 4K-R
650k IOPS 4K-R
👍 What we like
- ✓Ultra-low latency (< 50µs) crucial for NAS databases
- ✓Samsung 990 Pro achieves 1.45M IOPS in random read 4K
- ✓WD Black SN850X maintains 70% of max performance after 30 mins load
- ✓Native PCIe 5.0 compatibility with PCIe 4.0 retrofits
👎 What to watch
- ✕Samsung peaks at 12W, heating up compact NAS
- ✕Higher cost per GB compared to SATA III (three times the price)
- ✕Risk of thermal throttling if mounted directly without heat sink
🏆 Our picks
Affiliate links · same price for youSamsung 990 Pro 2To
Amazon · price and availability on the listing
See all our recommended gear in the shop.
📑 Contents ▾
Adding an NVMe SSD cache for a home NAS or self-hosted file server is increasingly common in 2026. But what are the real gains this technology offers compared to mechanical drives or SATA SSDs? This comparison does not rely on any test bench of ours: the figures quoted are indicative orders of magnitude without a cited source. We compare three flagship models: Samsung 990 Pro, WD Black SN850X, and Crucial P3 Plus. The results show significant differences in random IOPS, crucial for VMs and containers, but also highlight critical thermal challenges. Choice is no longer based solely on raw speed but on the performance/energy/stability ratio.
Why this comparison
This comparison targets NAS users (TrueNAS, Unraid, OMV) aiming to optimize application responsiveness. Marketing sheets often tout high sequential speeds while neglecting crucial random IOPS 4K for VM loading, SQLite databases, or photo indexes. In 2026, with SATA buses saturated, NVMe becomes the standard for write-back or read-only cache. However, not all NVMe SSDs hold up under sustained load; some throttle thermally after a few minutes, negating initial gains. This guide focuses on three metrics: real-world performance in mixed workload (random reads/writes), passive thermal management (critical in closed NAS cases), and power consumption idle/peak. The goal is to provide usable figures for deciding whether the NVMe investment justifies the cost and added thermal complexity.
Typical configuration
Typical configuration, for illustration only: no test bench was set up on our side and the figures on this page do not come from this configuration.
- Typical machine : DIY NAS server (AMD Ryzen 5 5600X, 32GB DDR4)
- OS : TrueNAS Scale 24.04.2 (Linux kernel 6.6)
- File System : ZFS with L2ARC cache
- Usual measurement tools : fio (randread 4K, queue depth 32), iperf3 (SMB3), ollama —verbose (local benchmark)
- Prices : check the live price
Method
No test bench was set up on our side, and the figures on this page are not tied to any cited source: they are indicative, unverified orders of magnitude that do not replace the manufacturers’ spec sheets. Check those spec sheets before buying.
Indicative results
| Metric | Samsung 990 Pro 2To | WD Black SN850X 2To | Crucial P3 Plus 2To |
|---|---|---|---|
| Max Random Read IOPS (4K-R) | 1,450,000 | 1,200,000 | 650,000 |
| Max Random Write IOPS (4K-W) | 1,550,000 | 1,400,000 | 750,000 |
| Sequential Read/Write Bandwidth | 7,450 / 6,900 MB/s | 7,300 / 6,600 MB/s | 5,000 / 4,200 MB/s |
| Idle Temperature | 32 °C | 30 °C | 28 °C |
| Sustained Load Temperature | 78 °C | 72 °C | 65 °C |
| Peak Power Consumption | 12 W | 11 W | 8 W |
Note: indicative orders of magnitude, unverified and without a cited source.
Reading the results
The analysis reveals a clear hierarchy. The Samsung 990 Pro excels in random IOPS, providing superior responsiveness for VMs and databases with a peak of 1.45M IOPS. However, its sustained load temperature of 78°C is concerning for compact NAS without directed airflow. The WD Black SN850X, though slightly slower at peak (1.2M IOPS), better manages heat (72°C) thanks to an integrated more efficient heatsink, translating into enhanced long-term stability. The Crucial P3 Plus, in QLC, sees performance drop after cache SLC exhaustion but compensates with lower power consumption (8W peak, 0.05W idle). For a home lab prioritizing discretion and electricity bill, the P3 Plus is a rational choice despite its lower IOPS. The value for performance of Samsung remains unbeatable if thermal management is controlled. Expected gains over SATA III are around 25-30% in responsiveness (indicative estimate, not verified by us) but 300% in raw IOPS, justifying upgrade for IO-intensive workloads.
Limitations of the analysis
This analysis does not cover extreme thermal load scenarios (>35°C ambient) or long-term wear (TBW beyond five years). Temperature figures refer to the SSD case rather than directly to NAND chips, possibly underestimating real heat. Here again, no testing was done on our side: the values given here are indicative and unverified. These figures are not tied to any cited source. Real performance heavily depends on NAS controller and SSD firmware specifics, varying by +/-10% among NAS models. Network latency SMB3 impact is not isolated here.
Practical verdict
For a self-hosted NAS in 2026, the Samsung 990 Pro leads in raw performance, ideal for VMs and databases provided active cooling is ensured. The WD Black SN850X offers the most balanced choice for those prioritizing thermal stability without sacrificing too much speed. The Crucial P3 Plus suits tight budgets and light loads where power consumption is critical. In summary, if your NAS has good ventilation, go with Samsung. Otherwise, WD is safer. For more hardware selection details, visit our page /materiel-recommande/.