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Although SSDs are gradually substituting HDDs, in some cases, you still need HDDs. When you buy HDDs online, you may be confused about 5400 vs 7200 RPM.
It’s generally thinking that 7200 RPM hard drives are superior to 5400 RPM. But when you search online, you may find some 7200 RPM hard drives are cheaper than some 5400 RPM. In this post, I will tell you why that scenario happens.
What Is Hard Drive RPM?
RPM, short for Revolutions Per minute, is used to describe rotational speed of a hard drive. Generally, the higher the speed, the better the disk performance. Why? The reason lies in the structure of HDDs.
As we all know, the HDD is mainly composed of parts like platters, read-write heads, a motor spindle, etc. The platters are used to store data and they are mounted on the motor spindle in parallel. Each storage surface of platters is equipped with a magnetic head used to write and read data.
The motor spindle drives the platters to rotate at several thousand revolutions per minute (RPM) so that the magnetic heads can be positioned at a specified position on the platter for reading and writing data.
Therefore, the faster the rotation speed, the faster the hard disk can find files, and the higher the transmission speed of the hard disk.
5400 RPM vs 7200 RPM
In this part, I will explain 5400 vs 7200 RPM just in terms of rotational speed, not touching upon other factors that affect HDD performance.
When other conditions are the same, 7200 RPM hard drives are superior to 5400 RPM hard drives in performance. Generally, 7200 RPM is at least 15% faster than 5400 RPM hard drives (just in theory).
In terms of sequential read and write capabilities, this gap is not significant. But in terms of random read and write capabilities, the gap between 7200 RPM hard drives and 5400 RPM hard drives is important, because this will affect the read and write speed for fragmented files and program startup speed.
Therefore, if you want to install OS or run programs on HDDs, you should choose 7200 RPM hard drives rather than 5400 RPM hard drives, which can make your OS or software run faster.
Compared with 7200 RPM hard drives, 5400 RPM hard drives have advantages such as low energy consumption, low heat production, low noise, and longer lifespan.
In general, higher rotation speed will bring some negative effects like temperature increase, increased motor spindle wear, increased working noise, etc. In addition, the increasing rotation speed will consume more power. When the more electricity is consumed per unit time, the working time of the battery will be shortened.
Based on the above features, 5400 RPM hard drives are usually used on notebooks and 7200 RPM hard drives are mostly used on desktops. Of course, if your laptop has good cooling performance, you can also install a 7200 RPM hard drive on it.
Is RPM Still Important Now?
With the improvement of areal density technology, RPM becomes less important nowadays. In this part, I will introduce areal density to you.
Areal density refers to the density of bits storage on the circular platters. When areal density increases on a hard drive, the data becomes more compact. The more compact the data, the quicker the head can get from bit to bit to read and write data. Therefore, areal density is another important factor that affects HDD performance.
LMR (Longitudinal Magnetic Recording)
LMR is the earliest magnetic recording mode. In this mode, the magnetization direction of the medium is parallel to the platter surface and follows the track. This will cause low magnetic density, because the medium will occupy a relatively large area.
PMR (Perpendicular Magnetic Recording)
To increase magnetic density, PMR comes out. In PMR, the magnetization direction of the medium is perpendicular to the platter surface. This mode is also called CMR (Conventional Magnetic Recording).
When the magnetic density increases, the disk performance improves. 5400 RPM hard drives crated by PMR technology can be faster than 7200 RPM hard drives created by LMR.
SMR (shingled magnetic recording)
To increase magnetic density further, manufacturers develops SMR based on PMR. SMR writes new tracks that overlap part of the previously written magnetic track, leaving the previous track narrower. In this way, it can increase areal density, but it is not as perfect as PMR and brings some defects.
The newly-purchased SMR disk may be no different from a non-SMR hard disk. However, after a period of use, when the disk space is gradually filled with data, the SMR disk will cause problems such as drop speed, decreased reliability, heat generation, and noise.
Anyway, RPM is less important nowadays. When you buy a new hard disk, you should take both RPM and areal density into consideration. If you want to know more about 5400 vs 7200 RPM and areal density, you can read the original text: 5400 RPM vs 7200 RPM: Is RPM Still Important?