FIVE TOP REASONS WHY SSDs ARE BETTER
1 SSDs are much faster
Several factors determine the speed of your hard drive. The rate at which data transfers from the motherboard to the drive is one, but that rarely has the greatest impact. More important is the fact that traditional hard drives are physical objects with moving parts, comprising their own internal motherboards, platters (like vinyl records) for storing data, and heads for reading and writing it (see box right).
To better understand how all these components can affect a drive’s speed, consider the difference between thinking about moving something across the room, and actually shifting it. Physically relocating an object requires that you go to the object, pick it up, move it, find a place to put it down, put it down, then sit back again. Now, how much time would it take you to just think about doing the same thing? No time at all.
It’s much the same story with a hard drive, which must get its platters spinning up to operational speeds, find somewhere to write (or read) your data, move its heads to that location, and either pick up (read) or put down
(write) the data in question. Doing the same with an SSD doesn’t require all that moving about: the drive can, effectively, ‘think’ about the data, which it writes to memory or recalls it. It’s then ready for use.
Platters that spin more slowly and heads that can’t get into position quickly will slow down a hard drive. Because the SSD doesn’t have these moving parts (as pictured below), they can on average read (open) data up to 10 times faster, and write (save) up to 20 times faster. Indeed, SSDs work so much faster than hard drives that a whole new interface – the connection between the drive and your motherboard — had to be invented to unleash their full potential. We’ll explore these in the next section.
2 SSDs are more robust
Hard drives are a lot more durable than they used to be, but with so many moving parts they’re still more prone to damage than an SSD. The platters need to keep spinning when reading or writing, and can’t be serviced like the wheels on a bike or car.
Perhaps more worryingly, they are also magnetic, like old cassette tapes, with the ones and zeros that comprise your data written as variations in the magnetic field. Rogue magnetic interference could be enough to corrupt that data or – in a worst-case scenario – wipe it altogether.
Solid-state drives aren’t magnetic. Instead, they use a series of ‘gates’ to regulate electrical charges to signify ones and zeros at specific locations within the SSD’s memory chips. These ones and zeros are the binary digits that relate to the characters and numbers that make up your documents, spreadsheets and photos (a capital letter A, for example, is represented as 01000001, B is 01000010, C is 01000011, and so on). Magnetic interference shouldn’t affect the charges recording those digits.
3 SSDs last longer
Typically, the life of a hard drive is calculated with reference to their ‘mean time between failures’, or MTBF. This states how many hours of use you could expect before it’s likely to die. Laboratory analysis shows that a hard drive can last up to 300,000 hours (34 years), while an SSD keeps going for 1.5 million hours (171 years). In the real world, hard drives can fail after three to five years, while SSDs can last up to 10.
Don’t imagine that just because an SSD has no moving parts, there’s nothing to wear out. Think back to those ‘gates’ we mentioned. The SSD opens and closes them by passing an electric charge through an insulator. This wears down very slightly every time it’s subjected to a current, with the inevitable result that, eventually, an SSD will fail, just as a hard drive will. It will just take much longer.
When choosing an SSD, you might see two other variables included in its specifications, aside from MTBF. These
are P/E Cycles and TBW. P/E Cycles are the number of times the data on a drive is written (programmed) and deleted (erased). TBW, on the other hand, is the number of Terabytes Written. In both cases, higher is always better, but watch out for warranties that specify, for example, 1000TBW or five years. In this case, your drive would be covered for five years, unless you saved more than 1,000 terabytes of data to it before five years had passed.
4 SSDs use less power
Without any moving parts, SSDs use less electricity. This isn’t only good for the environment: it also means you should be able to run a laptop on its battery for longer (typically between 30 and 45 minutes), which will be welcome news for anyone who works in coffee shops and libraries.
The moving parts in a hard drive can also generate more heat than an SSD. That makes it more likely your computer will run its fans, which can be a significant drain on a laptop’s battery.
5 SSDs are quieter
With no moving parts, SSDs are silent. This is ideal for anyone who uses their computer to make music or voice recordings, which can be marred by the annoying clicks, grinds and whirrs of a hard drive. In fact, anyone with an ageing computer is likely to suffer from a noisy hard drive, as wear and tear takes its toll. Although you might by now have got used to the noise, you’ll be surprised by how pleasant it can be when switching to an SSD eliminates the cacophony.