General

Brand	Samsung
Model	PM840
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	TLC
Drive Writes Per Day	0.1
Total Bytes Written	45 TBW

Performance

Sequential Read	530 MB/s
Sequential Write	250 MB/s
Random Read IOPS	96000
Random Write IOPS	44000
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 earlier MZ-7PC256, the Samsung PM840 MZ7TD256HAFV-000L7 delivers a clear generational shift toward better cost efficiency with TLC NAND while still pushing near-SATA-limit 530 MB/s sequential reads and up to 96,000/44,000 IOPS, giving it stronger value for read-focused client and OEM deployments. With 256GB capacity, 45 TBW endurance, and 0.1 DWPD, this model is best positioned for boot drives, office productivity systems, and light VDI endpoints where fast read responsiveness matters more than heavy write endurance.

Endurance & Reliability

With an endurance rating of 45 TBW and 0.1 DWPD, this 256GB SSD is well suited for light to moderate write workloads such as operating system, boot, office, and general business application storage. In typical system-disk use, where daily writes are relatively low, this level of endurance can comfortably support long-term deployment and is generally sufficient for many years of stable operation. Its specified UBER of 1.0E-15 means the drive is designed for a very low rate of unrecoverable read errors, supporting dependable data reads in normal enterprise use. This model does not include power loss protection (PLP), so while it remains a reliable choice for non-cache, non-write-critical applications, systems that face sudden power interruption risk should use proper shutdown control or external power protection.

Technical Specs & Insights

1. The SATA interface, paired with near-bus-limit sequential read performance, makes this drive a practical drop-in upgrade for enterprise servers that need faster boot, backup, and data streaming without changing existing storage infrastructure.

2. Its strong random read capability helps VDI, OLTP, and metadata-heavy workloads return small-block data quickly, improving user responsiveness when many requests hit the drive at once.

3. The low DWPD rating positions it best for read-centric enterprise use cases such as boot drives, content repositories, and reference datasets, rather than write-intensive logging or database journaling.

4. TLC NAND provides a cost-efficient balance of capacity, speed, and reliability, making it well suited for organizations optimizing storage density and budget across large deployments.

5. The very low typical latency supports faster transaction acknowledgement and more predictable application behavior, which is especially valuable in virtualized environments and latency-sensitive read paths.

Capacity Sweet

Lower capacity reference: 128GB Higher capacity reference: 512GB Within this series, 256GB is the sweet-spot capacity. Compared with the 128GB model, it provides noticeably more headroom for OS images, application binaries, logs, swap space, and routine patch growth, helping avoid early capacity bottlenecks. Compared with the 512GB model, it preserves essentially the same mainstream enterprise sequential and random I/O behavior while offering a more efficient cost-to-usable-capacity balance. This makes the 256GB version a strong fit for mid-sized deployments, such as hosting boot and utility volumes for roughly 40 to 60 virtualized infrastructure nodes.

FAQ