According to the quality level of FLASH chip, generally divided into: A+, A, s, self styled, white, black.

Because of the brand, grade and other factors caused the market chip prices, so that the SSD market is also confused. Generally we say A+ (original ALRIJNOL chip), A (original ALRIJNOL chip) chip in the use of the SSD will not appear any problems. So, what is the "white", what is "black", what is "self"? Here we focus on that, white and black -.

Self sealing chip is from buyers from the original purchase wafers, self cutting package inspection, is ultimately through the authentication is not known, but such chips relative to the original factory cutting out of the test chip prices lower, quality is relatively blank black piece is better. The "white" and "black" is a very popular name, definition and not too professional. To make it clear, you have to look at some of the concepts of wafer fabrication..

we start with a full wafer (Wafer).:

The Intel 25nm NAND Wafer

Wafer:wafer is the wafer shown in the picture, consisting of pure silicon (Si).. Generally divided into 6 inches, 8 inches, 12 inches specifications, the chip is based on the production of the wafer. A small Wafer, is a circular wafer, die, has become a particle package. A chip containing the Flash wafer wafer wafer, Nand first cut, and then tested, will be intact, stable, enough capacity of the die to take down, the package formed the daily Flash Nand chip. So, the remaining on the wafer, or is not stable, or is part of the damage so insufficient capacity, or is completely damaged. The factory takes into account the quality assurance, will this die announced the death, strictly defined as scrap scrap disposal. 

After the quality qualified die cut down, the original wafer on the picture looks like, is the rest of the Flash Wafer Downgrade.

These remnants of die are actually substandard wafers for quality. Is dug go part, which is part of the black, is a qualified die, are the original packaging production finished NAND pellet, and unqualified is left in the figure are used as waste disposed of.

Said so much, we should of a wafer manufacturing process has certain understanding, that is to say, the wafer production, qualified die by plant leaves to package into particles, unqualified die unit become defective products be abandoned without. This stay a toss, they became the original film and black film ". From this we can immediately be able to know that the original tablet is a higher price of the product, while the black film because of being treated as garbage, the sale price is very low, according to tons of calculation. Some of these bad Flash are capacity, some life can not meet the requirements, some of the test can not pass.

So what's the white piece? In fact, the white chip is the original film after the package to detect flawed particles, and then eliminated the garbage. Genuine NAND is not white tablets. But the foundry in order to recover part of the cost of manufacturing, will not hit the subject of the tablets sold to the downstream channel, and then these channels will be sold on the white chip other logo for sale.

Therefore, the piece of black and white films are actually scraps generated in the process of chip manufacturing, the black piece is eliminated in the raw materials stage part of the and white film is finished after the detection of the failure of the defective products. As we all know, the leftover bits and pieces also have the use value, then there have a chain, that is chip industry, waste recycling.

There are still parts of the black chip can be in the form of the wafer to the downstream packaging plant, because the factory will not have the problem die. These problems die through the downstream packaging plant testing, screening, but also the part of the reuse can leave the package sold. Black film is not the original plant, the downstream manufacturers themselves, so the appearance looks very rough, and often not hit the target. Many cheap MP3, U disk, that is made of black film.

White film is the packaging and then eliminated the particles, so only the form of particles, but also the original factory package, the only difference is not marked with the original piece. These white will be sold after the test, after the screening in the downstream, but will re marking (non original standard).

From the quality, black NAND chip is very bad, because the original factory has to the sentenced to death, just downstream plant will the reduced capacity to sell, also is castration, but quality is still very poor, buy the particles is equal to gambling. White chip NAND quality is still a certain guarantee, and then screened, then the performance and life of the index is closer to the original film. Very poor due to the black NAND chip reliability and even cottage SSD are not used, they will choose more secure white NAND, although sold SSD repair rate is high, but with the price advantage, cottage SSD still have certain sales.

In general, black piece refers to chip plant to be elected to the elimination of the defective, there was no factory label and product types of chip;

White film is better than the black chip selection of good quality, artificially to hit a variety of targets, but not the original chip factory label.

Since SSD uses flash memory chip as the storage medium, the quality of the chip is uneven.. It is very likely that SSD performance overall performance degradation as a result of a defective chip, and pieces of black / white film is to deceive the public and get out, let a person is difficult to identify.From the current situation, we have no good method to determine the quality of flash chip before purchase (unless the screwdriver is disassembled, or later tested)..

Then at present according to the chip storage quality ranking as follows: Toshiba (InnoDisk and pavement quality indicator (PQI) were used in Toshiba), Samsung (self-produced), magnesium (Intel), hy Han generation (domestic brands).

Although the life of flash has long have short, but due to the PCB (3-5 years of life), capacitors, management system and environment factors, affect SSD final service life.