What is the difference between a solid state drive and a mechanical hard drive?

(SSD) Solid State Drive

Solid State Drives (Solid State Drives) are hard drives made of solid-state electronic memory chip arrays. There are two types of storage media for solid-state drives, one is to use FLASH chips as storage media, and the other is to use DRAM as storage media. Now the mainstream uses FLASH flash memory chips as storage media. The operating temperature range of solid-state drives is relatively wide, ranging from 0 to 70 degrees for commercial products and -40 to 85 degrees for industrial products. At present, the mainstream interfaces are basically M.2 and SATA3.

(HHD) mechanical hard drive

The mechanical hard disk is a traditional ordinary hard disk, which is mainly composed of: platter, magnetic head, platter rotating shaft and control motor, magnetic head controller, data converter, interface, cache and other parts. The magnetic head can move along the radial direction of the platter, plus the high-speed rotation of the platter several thousand revolutions per minute, the magnetic head can be positioned at the designated position of the platter to perform data read and write operations. The information is written to the disk by the electromagnetic current through the magnetic head which is very close to the magnetic surface and the polarity is changed by the electromagnetic current, and the information can be read in the opposite way. As a precision device, the hard disk is the enemy of dust, so the air entering the hard disk must be filtered.

Performance comparison of solid state drives and mechanical hard drives

1. Write speed comparison:

The reading speed limit of HDD hard disk is 200M per second, and the writing speed is difficult to exceed 100M per second; SSD hard disk has a great advantage in transmission speed. Taking the MX series SSD as an example, the sequential write speed is as high as 510MB /s, the reading speed reaches 560MB/s, and it only takes a few seconds for a 1G file to complete.

2. Data security comparison:

The traditional HDD hard disk reads and writes data by reading the platter with the magnetic head. During the high-speed rotation process, the collision between the platter and the magnetic head is more likely to cause data damage, while the SSD hard disk does not have platters, as long as the chips are not deformed by external extrusion. , the data can be safely stored, so the difference between mechanical hard drives and solid-state drives in terms of data security is very big.

3. Economical and convenient comparison:

SSD hard drives have great advantages in speed, but due to higher cost, the current price of SSD hard drives is generally 2-3 times that of HDD hard drives, but with the continuous development of Moore's Law, the density of solid-state drives NAND flash memory chips will increase Large, the storage capacity is getting higher and higher. Large-capacity hard drives such as 500G solid-state hard drives and 1T solid-state hard drives can greatly meet user needs, and the cost performance is greatly improved. At the same time, the SSD solid state drive has the advantage in volume and quality, and has better shock resistance, which is more convenient for users who often take the computer on business trips.

4. Power consumption and noise comparison:

The high-speed rotating platter of HDD hard disk needs a high-power motor to drive, while SSD hard disk does not need a motor to drive, so the power consumption of HDD hard disk is much larger. Due to the rotation of the motor during operation, there will be slight vibration and vibration. Noise, and SSD hard drives do not have these problems.

5. Capacity comparison:

The traditional HDD hard disk has a large capacity, the current mainstream hard disk capacity is 500G ~ 2TB, and now the mainstream capacity of the SSD hard disk is 128G or 256G. of favor.

6. Comparison of seismic capacity

The traditional mechanical hard disk has a high-speed magnetic head inside, and its shock resistance is very poor. Therefore, if the general mechanical hard disk is used in motion or in a vibration environment, it is easy to damage the hard disk. The mechanical hard disk adopts a chip storage solution, has no magnetic head inside, is not afraid of collision, shock and vibration, and has super shock resistance, so that it will not affect normal use even in the case of high-speed movement or even with flipping and tilting. The possibility of data loss is minimized in the event of an accidental drop or collision with a hard object.

Let’s talk about the conclusion first: if the budget is limited, buy a solid-state drive, and the mainstream choice is a mix of solid-state drives and mechanical hard drives, but if the budget is abundant, choose pure solid-state drives.

First of all, the capacity of solid-state drives is not very low. It may be because the mainstream solid-state drives are 128GB/256GB of small capacity, so we feel that the memory is small.

Most people can accept the price of a 512GB SSD at a price of around 1,500 yuan. There are also many solid-state drives with a capacity of more than 4TB used in servers, but the price is particularly expensive.

The advantage of mechanical hard drives is that the technology is relatively mature, and the price is not very expensive. If you say that the reading speed is slow, the reading speed will not be slow to Africa.

Although the solid state can reach several times the reading speed of a mechanical hard drive, sometimes, some movies and documents are not actually improved much when placed in the solid state.

But be careful, don't choose slow mechanical hard drives, 5400 rpm and 7200 rpm are actually very different.

Therefore, some mechanical hard drives are particularly slow when reading and writing fragmented files, and at this time, the speed of solid-state drives is dozens of times better than it.

To give a practical example, after the system has been used for a long time, the boot time of the mechanical hard disk is mostly 1 minute, and in some extreme cases, it may be turned on for 3 minutes, and the hard disk is still reading things after entering, and it will take a while before it can be used.

If you use a solid state drive, you can basically get in in more than 10 seconds, and you don't have to wait after entering.

It's true that SSDs have a limit on the number of writes.

However, in fact, even if you write a lot of this solid-state drive, it can last for a long time, and the lifespan is proportional to the capacity of the solid-state drive. When the capacity doubles, the lifespan will double. It is estimated that it will take ten years to fully write a 128GB solid-state drive. .

The main cause of failure in SSDs today is unexpected power outages, rather than running out of flash memory.

Because of its mechanical structure, the mechanical hard disk is a precision device. Vibration and high temperature will cause damage to the mechanical hard disk. Even if it is well maintained, the disk will still be damaged.

A mechanical hard drive will generally break down for a few years, and it is actually not as durable as a solid-state hard drive.

Of course, it is not practical to install a computer with a pure solid-state combination, because large-capacity SSDs are indeed very expensive.