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Silver 2.5 inch enterprise hard drive with SAS connector

Seagate

Seagate Constellation.2 HDD-ST91000640SS 1TB 7200 RPM 64MB SAS 6Gb/s 2.5" laptop hard drive

SKU CH-XMTR-1T8QG MPN HDD-ST91000640SS

A 2.5-inch 1TB enterprise drive with 7200 RPM, 64MB cache, SAS 6Gb/s interface and 1.4M-hour MTBF for dense data-centre storage

  • Total capacity1 TB
  • Interface typeSAS 6Gb/s
  • Form factor2.5 in (6.35 cm)
  • Packaging typeRetail
  • Cache memory64 MB
  • Mean latency4.16 ms
  • Enterprise capacity in a 2.5" form factor fits dense data centres
  • 7200 RPM and 64 MB cache deliver fast data access
  • SAS 6Gb/s interface ensures scalable, high-integrity connectivity
  • 4M-hour MTBF and 0.62% AFR provide 24×7 reliability
  • Average 6.4 W operation cuts power use by up to 41%

1TB SAS 2.5" enterprise drive

The Seagate Constellation.2 HDD-ST91000640SS is a 1TB 2.5-inch internal hard drive built for dense data-centre environments. It spins at 7200 RPM with a 64MB cache and connects through a SAS 6Gb/s interface. The format lets operators store twice as much data in the same footprint as earlier 2.5-inch models.

SAS 6Gb/s interface and cache

The 6Gb/s SAS link provides dual-port connectivity with improved data integrity and scalability for multi-drive arrays. A 64MB cache buffers bursts of read and write traffic to smooth latency under heavy concurrent workloads. Enhanced PowerChoice technology cuts idle power by up to 54% compared with standard operation.

Power and vibration limits

Average power draw stays below 6.4W, which is up to 41% less than typical 3.5-inch nearline drives. Rotational vibration tolerance is rated for high spindle-density chassis, though performance will vary if the enclosure lacks adequate airflow. The 4.16ms average latency and 1.4M-hour MTBF reflect sustained 24×7 operation rather than peak throughput.

How it compares

Measured against everything we stock in 2.5-Inch Internal Laptop HDDs, at today’s prices. Recalculated every night.

Price $191.99
Pricier than about 83% of the 645 comparable items (median $66.99).
Total capacity 1 TB
Higher than about 90% of the 419 comparable items (median 320 GB).
Price per TB $191.99 per TB
Cheaper than about 57% of the 416 comparable items (median $233.48 per TB).

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Specifications

Product
Brand nameSeagate
Product lineConstellation.2
Model nameHDD-ST91000640SS
Total capacity1 TB
Performance
Mean latency4.16 ms
Rotational speed7,200 RPM
Storage
Cache memory64 MB
Ports & slots
Interface typeSAS 6Gb/s
Size & build
Form factor2.5 in (6.35 cm)
Shipping weight0.20 kg
Package size152 × 95 × 25 mm

Questions about this item

What is the MTBF rating and annualized failure rate for the Constellation.2 ST91000640SS?

The drive has a mean-time-between-failures rating of 1.4M hours and an annualized failure rate of 0.62%, designed for 24×7 nearline operation.

What is the maximum sustained power draw for the ST91000640SS under heavy workload?

The Constellation.2 operates at fewer than 6.4W on average, the lowest operating power in its class for a 7200-RPM enterprise drive.

How much heat and noise does the 2.5-inch SAS drive produce when running continuously in a server?

Workload Management technology helps systems keep drives cool, while enhanced PowerChoice technology saves up to 54% energy during idle or slow periods.

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