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Solid State Drives – Why Are They So Fast?

For most people, an HDD or hard disk drive inside their computer is the flat broad box that stores their Operating System, files, documents, and other essentials. So far, not many users were aware of the inner workings of their HDD. Lately, with speeds of computers going up many folds, people have started looking at alternatives for the HDD – the SSD or the Solid State Drive.

Whatever else you change in your computer system, the general experience remains the same. For example, you may get a new display, add more RAM or install a new graphics card. Barring a few moments of exhilaration, you do not experience the constant euphoria that you get when you replace your regular HDD with an SSD.

An SSD suddenly transforms your computer into a high-speed demon. Additionally, you get this feeling every time you use the computer. Even if you do not realize this increase in speed with an SSD, you will appreciate it as soon as you have to revert to operating a computer with a regular HDD. It is truly amazing the way this new technology is helping to transform our computer experience.

To understand the functioning of SSDs, it is necessary to know the computer’s inner structure or architecture regarding its memory. A computer’s memory architecture is actually made up of three sections: the cache, the temporary memory and the actual memory storage itself.

The CPU or the Central Processing Unit of a computer is intimately connected to the cache memory and accesses it almost instantaneously. As the computer operates, the CPU uses the cache memory as a sort of scratch pad for all its interim calculations and procedures.

The temporary memory, also known as the RAM or Random Access Memory of a computer is the place where the CPU stores information related to all the active programs and running processes. Although the CPU can access the RAM at high speeds, the access is slower than that for cache memory.

For permanent storage, your computer uses the memory within the HDD or the SSD. These may be programs, documents, configuration files, movie files, songs, and many more. Unlike cache and RAM, an HDD or an SSD retains its contents even when the computer has been shut down.

When people replace their HDD with an SSD, their computer operates at a higher speed even when they have not updated their cache or RAM. This is fundamentally because of the difference in the way of working of an HDD and an SSD.

An HDD is essentially an electromagnetic device. Inside, there is a motor to spin the several magnetic platters stacked one on top of the other. Before the CPU can read data from the magnetic plates, they have to spin until the right sector comes under the reading heads, which then move in to read from the exact location. All this mechanical movement takes time.

On the other hand, the SSD, being an all-electronic device, involves no mechanical movements. It uses a grid of electrical cells to store and retrieve data. Moreover, these cells are further separated into sections called pages. Further, pages are clumped together to form blocks. All this contributes to the fantastic speed of an SSD.

SSD, Magnetic or Hybrid Drives

Earlier, when we did not have much of a choice, PC storage options were limited to the largest capacity hard disk drive one could afford. Those days are long gone and today the average customer has to juggle between selecting different types of storage media apart from their capacity. Although it is fairly important to select the most optimum storage medium for a specific application, each of the drive types has their own advantages and disadvantages.

Magnetic hard disk drives have long been the default storage component for both desktop and laptop computers. Although the latest magnetic drives are very much advanced and better performing compared to their brethren from yesteryears, their underlying technology has remained mostly unchanged. Magnetic hard drives essentially consist of stiff magnetic platters rotating at high speeds paired with read/write heads travelling over their surface to retrieve or record data.

Magnetic hard disk drive technology is mature. Manufacturers now make highly reliable drives that users can purchase at much lower prices as compared with other storage options – most magnetic hard drives cost only a few cents per gigabyte. Moreover, they are available in relatively high capacities, going up to 4TB. Modern magnetic hard drives connect via the SATA or Serial ATA interface and do not require any special software for the operating system to recognize them. In short, magnetic hard disk drives are dirt-cheap, simple to operate and spacious.

However, the disadvantage with magnetic hard disk drives is their low storage or retrieval speeds compared to the SSDs and Hybrid products. The read and write speed depends on how fast the platter rotates – a 7200-RPM drive is faster than a 5400-RPM drive, but both are significantly slower than SSDs or even hybrid drives.

If you are just an average PC user sticking mostly to using mail, browsing the Web, and some amount of document editing, a standard magnetic hard disk drive should serve you fine.

SSDs or Solid State Drives are so called because unlike the magnetic drives, they do not have any moving parts – they are typically nonvolatile NAND flash memory. Although most SSDs connect via the SATA interface, there are PCI Express-based SSDs that offer ultrahigh-performances. SSDs store data and file just as any other drive does.

Since SSDs do not have any moving parts, they can operate at blazing speeds such as 500MB per second on average accessing data in just a few milliseconds. Compare this with the speed of a magnetic hard disk – 200MBps with access times just a shade below 8ms. In short, with SSDs you have a much snappier and a much more responsive system. With SSDs, everything is faster – boot times, application launch times and file-transfer speeds.

Without moving parts, SSDs are not susceptible to damage or degradation due to movement or vibrations. The two disadvantages with SSDs are their cost per gigabyte and their read/write life. At present, they cost about $1 per gigabyte.

Manufacturers offer Hybrid drives as a go-between. These are mostly magnetic hard drives with some SSD thrown in. The most frequently accessed data is stored in the SSD. That makes for high speed while the cost is kept low.