Comparison and evaluation of solid State hard disk and common hard disk

the difference between SSD and common hard disk

In fact SSD solid-state drives are solid-state storage, belong to flash memory, long service life, not easy to damage, strong earthquake resistance. The disadvantage is: The price is expensive, the capacity is small.

Ordinary hard drive inside a platter, work through high-speed rotation to read and write information, very afraid of vibration, easy to damage, the advantage is mature technology, low price, large capacity, so the popularity of a long time, wide area.

SSD solid-state drives can improve computer performance in addition to its faster reading speed than ordinary hard drives. such as the installation of SSD solid disk as a system disk, into the system time than ordinary faster than 20%, open like 3DMAX, Photoshop and other applications faster than the normal speed of many.

There may be a lot of people who don't know the exact difference between SSD and HDD, and often hear people ask: why is SSD so much faster than HDD? What is the difference between SSD and traditional hard disk? Well, here's a detailed answer to your questions, to see the advantages and disadvantages of SSD and HDD.

The specific structure of this HDD hard drive is not detailed, we all know HDD hard disk is a mechanical structure, affecting performance of the main motor speed, disk density, head number, cache capacity, and other factors, but not the point.

Improve HDD performance is mainly by improving the speed, the current mainstream is 7200RPM, high level of civil 10000-15000rpm, but high speed means that the noise, power consumption, the design of the motor is very harsh, not to mention can be mentioned.

Disk density is also a way to improve performance, from the ancestor of the IBM Winchester (delivered genre) hard disk has been using the magneto-resistive effect, the latest is from GMR to vertical records of PMR changes.

HDD's mechanical structure determines that it can not be qualitative change, in fact, in addition to the disk density in recent years, there is still room for technological progress, HDD drive speed stayed at the 7200RPM level has been seven or eight years, the current strongest HDD hard drive continuous reading speed does not exceed the 200mb/s level, 4KB randomness can be the absolute cup.

SSD's physical composition is basically flash memory + main control + cache +pcb+ interface, no mechanical parts, data reading and writing are electronic signals, there is no bottleneck such as motor speed, performance naturally comes up.

Speaking of performance, there is one thing to admit, the latest HDD hard disk read and write speed is not bad, such as Hitachi's previous release of 4TB hard disk, write speed is also 160mb/s, burst speed even on the 477mb/s, write speed can almost be comparable to some low-end SSD.

But in small file random performance, HDD is completely powerless, for example, SSD's random read delay is only a fraction milliseconds, and 7200RPM random read latency of 7 milliseconds, 5400RPM hard drive is up to 9 milliseconds, the response in performance is random read ability is far less than SSD, This is most evident in the speed of the switch machine.

Random Read and write and boot speed is the place where the HDD never catches the SSD.

Only one example of random performance can be used to kill HDD hard drives, and SSD has advantages over HDD in other ways, but SSD is at a disadvantage in terms of capacity and price:

1. Volume and Weight: SSD victory

2. Noise and Vibration: SSD again, absolute mute, and HDD noise can be high and low, some enough to make people crazy, and vibration is a problem to consider.

3. Temperature: HDD Work when the highest temperature of about forty or fifty degrees, SSD to low, but this problem has little impact.

4. Power consumption: HDD maximum power consumption of about 5-10w, and SSD is usually less than 3W, the same problem impact is not large, enterprise-class users on the other.

5. Capacity: HDD wins, civilian-grade SSD generally does not exceed 1TB, and HDD biggest already has 4TB.

6. Price: HDD wins, and the larger the capacity, the more obvious the HDD advantage.

The latter two are the most destructive reasons for HDD manufacturers such as Seagate and the West, SSDs in the past is indeed more expensive, the audience group small, less than the HDD so affordable, but with the progress of technology, SSDs per GB cost is also falling rapidly, especially in recent years, SSDs price war is very fierce, The previous 128GB SSD price is usually around 1200 yuan, but Samsung, the United States and light 128GB products now only more than 800 yuan, and even more than 780 products, has been close to the user's psychological defense.

Some 60/64GB SSD even less than 400 yuan, make the system disk very suitable, and 120/128GB model in addition to install the system, but also can retain most of the space to pack large software and games, enough users use.

The argument between SSD and HDD has not subsided, the two are not simply replaced, replaced by the relationship, in the current large price, blocking the spread of SSDs the last line of defense is also beginning to collapse, and upgrade SSD brings more experience than upgrading the CPU, memory is also obvious, the switch is faster, Software and game loading speed is almost instantaneous, with this advantage, we have any reason to reject SSDs?

To sum up, the difference between SSD and ordinary hard disk mainly has the following points:

1, speed, solid-state hard drive transmission speed can reach 500mb/s, which read speed to 400-600MB per second, write speed of 200MB per second. And the traditional hard disk read speed limit can not exceed 200MB per second, write speed in 100MB per second or so. If a discontinuous scatter data is encountered, the SSD can express the extremely fast reading and writing speed. But the traditional mechanical hard disk because of the magnetic head seek the way and so on, the transmission speed is slow.

2, safe, solid-state hard disk does not have a platter, so long as its chip is not affected by the shape of extrusion deformation, data can be safely saved. The traditional hard disk does not have this advantage, once in the high-speed rotation process of the disc and head collision, or even unreasonable contact, will cause the disc damage, data loss.

3, the economy, in the same capacity, solid-state drives at this stage of the price is higher than the traditional hard drive 3-5 times, but with Moore's law forward, solid-state hard disk NAND flash chip density will be more and more, the storage volume is higher, will one day replace the traditional secondary storage devices.

The benefits of solid-state drives

Speaking of the benefits of solid-state drives, the first flush is faster than ordinary hard disk speed, through the test we can find solid-state hard disk reading speed is nearly twice times the average hard drive. In addition, solid-state drives are more stable without noise.

In fact SSD solid-state drives are solid-state storage, belong to flash memory, long service life, not easy to damage, strong earthquake resistance. The disadvantage is: The price is expensive, the capacity is small.

Ordinary hard drive inside a platter, work through high-speed rotation to read and write information, very afraid of vibration, easy to damage, the advantage is mature technology, low price, large capacity, so the popularity of a long time, wide area.

SSD solid-state drives can improve computer performance in addition to its faster reading speed than ordinary hard drives. such as the installation of SSD solid disk as a system disk, into the system time than ordinary faster than 20%, open like 3DMAX, Photoshop and other applications faster than the normal speed of many.

The difference between SSD and ordinary hard drive

Solid-state drives are compared to ordinary hard drives with the following advantages:

1. Start fast, no motor speed up the rotation process.

2. No head, Fast random read, very little reading delay. According to the relevant test: two computers in the same configuration of the computer, the laptop with solid state drive from the boot to the desktop has taken a total of only 18 seconds, and the laptop with the traditional hard drive for 31 seconds, nearly half the two gap.

3. Relatively fixed read time. Because the addressing time is independent of the data storage location, disk fragmentation does not affect the read time.

4. DRAM based solid-state hard disk write speed is very fast.

5. No noise. Because there are no mechanical motors and fans, the noise value at work is 0 db. Some high-end or high-volume products are equipped with fans and therefore still generate noise.

6. Low-capacity flash-based solid-state drives have lower energy consumption and calorific value in the working state, but higher energy consumption for high-end or high-volume products.

7. There is no mechanical moving parts, no mechanical failure, no fear of collision, shock, vibration. This will not affect normal use even in the case of high-speed movement or even rollover tilt, and can minimize the likelihood of data loss if a laptop falls accidentally or collides with a hard object.

8. Working temperature range is larger. A typical hard drive can only work within a range of 5-55 degrees Celsius. Most solid-state drives can work in-10~70摄氏度, and some industrial solid-state drives can work in-40~85摄氏度, or even a larger temperature range.

9. Low volume solid-state drives are smaller and lighter than the same volume. But this advantage gradually weakens with the increase of capacity. Until 256GB, solid-state drives are still lighter than ordinary hard drives of the same capacity. Computer Tutorials

Solid State hard disk is the biggest shortage is expensive, relative to ordinary hard drives, prices do not have any advantages, users in the use of the sense of the application gap is not obvious, the other solid-state hard disk capacity is small, can not meet the large storage data needs. But as technology improves, the future of solid-state hard disks remains to be seen.

Solid-State hard disk has many advantages, compared to the traditional mechanical hard disk boot fast, read delay small, write speed, no noise, low calorific value, anti-vibration, etc., but the high price has become its popularity and application of the biggest obstacle.

"The manufacturing cost of solid-state drives is higher than that of ordinary hard drives. "The cost per unit capacity of solid-state drives is 5~10 times (based on flash memory) and even 200~300 times (based on DRAM)," said the pool engineer. At the same time, the capacity of solid-state hard disk is also far below the ordinary hard drive, the common solid-state hard disk capacity is generally below 1T, and ordinary hard disk capacity is far more than this number.

Pool engineers point out that in terms of data recovery, the average hard drive also has a slightly better upper hand than a solid-state drive. Once the hard drive is damaged, if it is a normal hard drive, data recovery may also save some of the data. But if it is solid-state storage, one but the chip is damaged, it is almost impossible to find the data in a chip that breaks into several lobes or is penetrated by the current. Of course, this is also the loss of storage space to compensate, but because of the current high cost of solid-state drives, this way to back up the price is not expensive.

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