Seagate Momentus 7200.5 750GB Hard Drive Review (ST9750420AS)

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The Largest Capacity Momentus Goes 4k

With the crush of SSDs on the storage market and falling prices of NAND, the trusty hard drive has fallen out of the consumer radar for the most part. Only when large capacities and/or external back up drives are needed do the spinning platter stalwarts get the call. Seagate hasn’t forgotten the hard drive business and they’ve been hard at work making improvements that don’t involve platter speeds or cache expansion which were the areas that saw the most change in the hard drive evolution in recent history. As such, Seagate sent us over a few drives to put through the wringer and the first up is there 2.5″ Momentus 750GB drive.

Seagate Momentus 750GB

The drive spins at 7200 RPM and uses a SATA II interface but it has a feature that gives it a performance edge. Namely, this is an Advance Format drive maintained by Seagate’s proprietary SmartAlign Technology with 4k sector alignment rather than the old 512 bytes alignment. What’s great about this is that the 4k alignment can cause issues with operating systems that don’t support it; however, the SmartAlign technology doesn’t really re-align the partitions but rather manages the read/writes dynamically without the OS ever seeing it or having to intervene. No external utilities or hassles for the user and with it comes performance perks as well as allowing Seagate to squeeze out more capacity.

Seagate Momentus 750GB

This particular drive does not contain a free-fall sensor module (found on the 500GB and 250GB models) which is highly recommended if you have plan on installing a drive in your laptop – although some laptops have this feature included in the hardware outside of the actual drive. Hard drive prices have really taken a hit as of late with the natural disasters in the east so the current going price is $149.99 online which, not too long ago, would have bought a 1.5TB drive or larger.

Seagate Momentus 750GB Specifications and Features


Model Number ST9750420AS
Interface SATA 3Gb/s
Cache 16MB
Capacity 750GB
Areal density (avg) 541Gb/in2
Guaranteed Sectors 1,465,149,168
Height 9.5mm (0.370 in)
Width 69.85mm (2.750 in)
Length 100.35mm (3.951 in)
Weight (typical) 115g (0.254 lb)
Spin Speed (RPM) 7200 RPM
Average latency 4.2ms
Random read seek time 11.0ms
Random write seek time 13.0ms
I/O data transfer rate 300MB/s
Unrecoverable read errors 1 in 1014
Annual Failure Rate 0.5%
5V start max current 1.0A
Average idle power 0.96W
Average seek power 2.5W
Ambient Temperature
Operating 0°–60°C
Nonoperating -40°–70°C
Maximum operating temperature change 20°C per hour
Maximum nonoperating temperature change 35°C per hour
Operating Shock (max) 350 Gs for 2ms
Nonoperating Shock (max) 1000 Gs for 1ms
Acoustics (Idle Volume) 2.3 bels
Acoustics (Seek Volume) 2.5 bels
Storage Type HDD
SmartAlign Yes


While the inner workings of the drive have been updated, the outside is virtually indistinguishable from other models/generations save for the model information on the sticker. The usual SATA data and power connectors are on one end next to a four pin jumper block. Even though this is a high capacity drive at 750GB, the height remains at 9.5mm which makes it compatible with just about any computer.

Seagate Momentus 750GB

Let’s have a look at the test system before we head to the benchmarks.

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