Until recently, lower-end and power-efficient laptop drives could be found with 4,200 or even 3,600 rpm spindle speeds (70 and 60 Hz), but these have fallen out of favour due to their lower performance, improvements in energy efficiency in faster models and the takeup of solid-state drives for use in slimline and ultraportable laptops. High-performance drives (used in fileservers and enthusiast-gaming PCs) rotate at 10,000 or 15,000 rpm (160 or 250 Hz), usually with higher-level SATA, SCSI or Fibre Channel interfaces and smaller platters to allow these higher speeds, the reduction in storage capacity and ultimate outer-edge speed paying off in much quicker access time and average transfer speed thanks to the high spin rate. Computer hard drives typically rotate at 5,400 or 7,200 rpm (90 or 120 Hz), the most common speeds for the ATA or SATA-based drives in consumer models.A piston aircraft engine typically rotates at a rate between 2,000 and 3,000 rpm (30–50 Hz).Thus an eight-cylinder engine turning 300 times per second will have an exhaust note of 1,200 Hz. The exhaust note of V8, V10, and V12 F1 cars has a much higher pitch than an I4 engine, because each of the cylinders of a four-stroke engine fires once for every two revolutions of the crankshaft. ![]()
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