General

Brand	Samsung
Model	840 PRO
Capacity	256GB
Usage Class	Client

Interface

Host Interface	SATA
Total Interface Bandwidth	6 Gb/s

Physical Dimension

Form Factor	2.5

Flash & Endurance

NAND Flash	MLC
Drive Writes Per Day	0.16
Total Bytes Written	73 TBW

Performance

Sequential Read	540 MB/s
Sequential Write	520 MB/s
Random Read IOPS	100000
Random Write IOPS	90000
Average Latency	50 μs

Reliability

Mean Time Between Failures	1.5 Million Hours
Uncorrectable Bit Error Rate	1.0×10⁻¹⁷
Power Loss Protection	No

Part Number

MPN	MZ-7PC256

Engineer's Note

Compared with the previous-generation MZ-7PC256, the Samsung 840 PRO 256GB (MZ-7PD256) pushes the SATA interface much closer to its ceiling at 540/520 MB/s and up to 100,000/90,000 IOPS, delivering a clear generational gain in low-latency random I/O and sustained write responsiveness at the same capacity point. Its MLC NAND and 73 TBW endurance make it a stronger fit than mainstream client SATA SSDs for write-sensitive workstation boot drives, developer systems, and read-heavy database or virtualization tiers that need premium SATA performance without moving to a PCIe platform.

Endurance & Reliability

With an endurance rating of 73 TBW and 0.16 DWPD, the MZ-7PD256 is well suited for typical read-heavy and mixed office workloads, including OS boot, application hosting, and general business use. In practical terms, this level of endurance is sufficient for a system drive that writes around 20 GB per day for about 10 years, giving procurement confidence for long-term standard deployment scenarios. From a reliability standpoint, the 1.0E-15 UBER means the drive is designed for a very low uncorrectable bit error rate, helping maintain data integrity during normal operation, while the 1.5 million-hour MTBF supports dependable continuous service. This model does not include power-loss protection, so it is best matched to environments with stable power or system-level backup protection, rather than write-critical applications where in-flight data during sudden outages must be preserved.

Technical Specs & Insights

1. Its SATA interface drives throughput close to the ceiling of legacy storage backplanes, making it a low-risk drop-in upgrade for enterprise servers and storage arrays without requiring PCIe changes.
2. Strong sequential read performance helps accelerate full-dataset scans, OS image delivery, and backup restore operations in read-focused infrastructure.
3. High random read capability keeps metadata-heavy databases, virtual desktop farms, and boot-storm scenarios responsive under concurrent access.
4. The modest endurance profile makes this model best suited to read-centric enterprise roles such as content repositories, reporting replicas, and system boot volumes rather than write-intensive logging tiers.
5. Enterprise MLC NAND paired with very low typical latency supports more predictable response times and better sustained consistency than consumer-oriented flash in transactional workloads.

Capacity Sweet

Lower capacity reference: 128GB Higher capacity reference: 512GB In this series, the 256GB MZ-7PD256 sits at the sweet spot for mainstream enterprise deployment. Compared with the 128GB model, it gives meaningfully more headroom for OS growth, patches, logs, swap, and application overhead, reducing early capacity pressure. Compared with the 512GB option, it preserves essentially the same enterprise-class sequential throughput and random IOPS profile while keeping acquisition cost and stranded capacity better controlled. This makes 256GB an efficient choice for mid-scale rollout, such as boot and utility storage for about 40 to 60 virtualization hosts or infrastructure nodes.

FAQ