ddr3 memory Why SSDs are getting worse and worse
solid state driveSSD OEM ddr3 memory now SSD capacity is rising ddr3 memory, the price is decreasing ddr3 memory, so that the upgrade SSD is becoming more and more popular, but evaluating the advantages and disadvantages of a hard disk should be considered from multiple dimensions, if you only pursue speed, you often end up in the unknown trap.
SSD-like technology appeared as early as the 1950s, and by the 1970s–1980s, it was used for high-end supercomputing. However, it was still very expensive, and 5-figure dollars could only buy about 2–20 MB of capacity. Later, SSD technology was also used in the military and aerospace fields, and gradually appeared in consumer devices in 1990, but the life span was “only” about 10 years, and it was not until Windows 10 was released in 2015 that it officially began to be popularized. It is called an SSD because it does not have the moving parts and rotating platters like traditional HDDs, and the internal parts of the SSD are fixed.
data in the SSD is stored in a memory chip called “Flash Flash”.
There are two types of flash memory: NOR and NAND. Both flash memory chips consist of many floating-gate transistors, which are the smallest units that store data, just as the magnetic material in an HDD represents 1s and 0s. Transistors make up the grid, and depending on the number of transistors in the grid, the capacity of a single grid is between 256kb-4MB.
the net result is that NAND flash memory costs less and can have more storage space in the same volume, which makes it more popular, and the products for individual consumers are NAND. NOR flash memory is suitable for low-density, high-speed read-only applications.
SSD is faster than HDD because the SSD’s master knows the exact location of all meshes, so when the system needs to use a file, the SSD can directly give it the response time in nanoseconds.
flash memory particles are constantly upgraded and iterated, in order of version: SLC, MLC, TLC, QLC, QLC is the latest (but worst).
transistors are the smallest units that store data, you can think of the entire hard disk as a bus, each transistor unit is a BUS, and the smallest unit of storing data electron (bit) is the passenger in the bus. Naturally, the more passengers in the bus, the greater the hard drive capacity.
single-level unit SLC era, the number of passengers is not large, each passenger can have 1 bus, that is, each unit only puts one data unit;
multi-layer unit MLC era, there are more passengers (everyone’s demand for hard disk capacity increases), but BUS is so big, what to do? Only two passengers can be placed on the same bus, that is, each bus stores two data units;
three-level unit TLC era, it was found that it was not enough, so it began to squeeze three passengers into the same bus. And the latest technology QLC is a bus for four people.
we all understand a truth, the more people, the more difficult it is to manage, the lower the efficiency (slow reading and writing), the more people use a thing, the faster it wears out (short life).
SLC is the original technology, it has low density, so the capacity is relatively small, but the fastest speed, and the service life is very long, but because it is too expensive, it is basically only used in enterprise storage. Prices are often thousands or tens of thousands;
MLC is a compromise option, although it is inferior to SLC in some aspects, but after considering the price, capacity, life, speed is the most suitable product for individual consumers, do system disk or large file processing, about 3 times cheaper than SLC, it is more recommended to use MLC as a system disk or store important data (stop production if you don’t buy it);
TLC is denser, and although caching technology is used, it is still not as fast as the first two, and the life span is 2-10 times less than the first two. Suitable for ordinary consumers, it is no problem to make system disks, game disks, temporary disks (U disks, mobile hard disks, etc.). The price is about half as cheap as MLC, and it is recommended to use TLC as a system disk, warehouse to store movies and games, etc.;
four-level unit QLC, as the name suggests. Although consumers are complaining about QLC, they can’t stop the pace of manufacturers making money, and QLC’s solid-state drives are rapidly gaining popularity. It is not recommended to buy QLC.
SD Every “technology upgrade” is the result of a trade-off, manufacturers are weighing costs and profits, consumers are weighing capacity and longevity, capacity is doubled, but the problem is also rising exponentially.
SLC uses two voltage changes to represent 0 or 1 (1bit), MLC uses 4 voltage changes to represent 11, 10, 01, 00 (2bit), TLC uses eight voltage changes (3bit), and QLC uses 16 (4bit). Each time the flash cell writes and modifies data, it changes the voltage state of the electron, and each state change results in isolated silicon oxide losses, which is the main cause of shortened life.
LC can erase an average of 100,000 cycles. MLC is only 35000-10000 cycles. TLC is about 5000. And QLC, the vendor claims to be consistent with TLC, do you believe it?
The normal read and write speed of most current NVMe protocols (described later) SSDs is about 1500 MB/s. But the QLC that is becoming widespread is only 80-160 MB/s (continuous write), which is slower than mechanical hard disks.
The life of TLC should be more than 5 years, but QLC is only 3-5 years, since the manufacturer has repeatedly stated that the new technology is good in all aspects, then why repeatedly shorten the hard disk warranty time?
different particles for different markets and groups of people is actually no problem, but most businesses will not specify the use of that kind of particles, because they want to sell different particles mixed, so that the “incomplete” new particles gradually replace stable old particles, a few years ago we still have many MLC hard disks to choose from, now almost only Samsung is still producing MLC hard disks, more profitable but less fast and life TLC has occupied the market.
Flash memory used to be arranged in a single layer, but at a cost cost, manufacturers now almost all storage stacks are stacked, called 3D flash. It’s not unusual to know that most of the 3D flash memory on the market these days. It is enough not to be fooled, there is no need to go into depth.
flash memory particles have a high technical threshold, and their business model is the same as memory, usually multiple manufacturers cooperate, the division of labor is generally Fab (production) and design house (design), and the final dominance must be in the hands of the producer (see Huawei and TSMC). People like SanDisk and Kingston belong to Design houses and package sellers, and the real big guys are still Fab that provides them with flash memory particles.
wafer and master
> 4K alignment is the alignment of the starting sector of a partition to the starting position of a 4K sector. Because of the characteristics of SSD flash memory particles, 4K alignment will greatly increase its read and write speed, so 4K alignment was required when solid-state first became popular, but now it is not necessary, and the system will automatically 4K alignment.
How much capacity is suitable and capacity not only affects the life, but also affects the read and write speed and life.
and the master will reasonably allocate storage tasks to flash memory particles to ensure that the amount of tasks in each unit is the same, so as to avoid only using a certain unit to cause the unit to die of overwork, the more people and the greater the strength, the larger the capacity, the fewer tasks divided equally, and the natural life is long.
128GB: Try to avoid hard disks of this capacity tend to have the worst performance due to the small number of memory modules. In addition, this capacity basically can’t do anything after installing the system, and upgrading to the next level doesn’t cost much.
250GB: This capacity is often used in the basic configuration of notebooks, daily office is basically enough, if the economy is tight, it can also be paired with HDD, and 500GB level is recommended.
500GB: Best value for money, although 1TB is more attractive, 500 GB is just right in terms of price and capacity. Both games and large files can be saved with HDDs, or deleted as soon as they are used up.
1, SSD only refers to a physical form of hard disk, the SSD principle and technology we use on the computer is no different from the built-in storage of today’s mobile phones, are flash memory + main control.
2, the era of traditional hard drives is not over. According to statistics, 85% of the world’s devices still only use mechanical hard disks, and most of the rest are a mix and match of SSDs and HDDs, and only SSD devices are only a few. SSD shipments are expected to surpass HDDs until 2021.
3, NVMe is faster than SATA, the latest SATA III has a maximum throughput of 600MB/s, while NVMe can be up to 3500MB/s. However, the improvement of NVMe compared to SATA can only be truly reflected in sequential read/write, which means “only large file reading and writing is effective”, so you may not feel the difference for gaming and daily work. However, for video editing, rendering and photo processing, NVMe has obvious advantages. solid state driveSSD OEMddr3 memory