SSD low energy consumption claims a myth: report

By Chris Nicholls

LOS ANGELES: The low energy consumption claims made by many SSD (Solid State Drive) hard disc manufacturers have been called in to question following a report stating many used more power than a standard hard disc.

According to the report, conducted by independent PC hardware review site Tom’s Hardware, the four 32 GB SSDs from various manufacturers tested reduced overall battery life in a Dell Latitude D630 notebook compared to a platter-based hard disc.

The reason, according to authors Patrick Schmidt and Achim Roos, was that a hard disc only uses idle power when not actually reading or writing, whereas an SSD only has active or idle states and draws full power when active.

“Most flash SSDs show power requirements … that are comparable to those of conventional 2.5-inch notebook hard drives. A typical 2.5-inch hard drive based on rotating magnetic platters usually requires between 0.5 W and 1.3 W when it runs idle, and from 2 W to around 4 W when it is under maximum load.

“In contrast, flash SSDs only seem to know two states: active or idle … So while conventional hard drives may operate at relatively low power when little movement is required — such as during sequential read access — flash based drives do not. They will draw their maximum power level constantly when in use, and as a consequence, simply spend more total time drawing maximum power than conventional drives,” the report stated.

The problem worsened when sizes diminished, the report stated, as 1.8-inch hard discs span at lower speeds, using less power than the 2.5-inch model tested, while size made no difference to an SSD’s power consumption.

While the authors acknowledged SSDs were faster than traditional hard discs in read/write speeds, they pointed out that for road warriors, losing up to an hour (in the worst case) of battery life could outweigh other considerations.

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