USAFRet :
envy14tpe :
I wonder if we could create a 2.5" or M.2 tier list. I feel like there are 3 segments for each. For 2.5", you got Samsung Pro level, Evo level, and then cheap level.
He who asks the question volunteers himself to do it...:lol:
So, go for it!
I know very little about SSDs, so I know this is going to piss off a lot of people.
Beginners Guide to SSDs
All the different SSD types appear to be the same speed when used for games and light work loads. So for a majority of computer users it shouldn't matter which SSD you choose as long as it is functioning properly.
If you wish to better understand the articles about SSDs you can continue reading.
There are basically 2 types of SSDs SATA SSDs and PCI Express SSDs.
SATA was designed for Hard Drives. SATA SSDs on a Sata III connector can run at around 4.8Gb/s while M.2 (pronounced m dot two) SSDs can reach 31.5Gb/s. SATA SSDs should work in all 3 SATA versions, although the data rate might vary. Here are the 3 SATA versions: Sata I 1.5Gb/s, Sata II 3Gb/s, Sata III 6Gb/s.
Mini-SATA (mSATA) interface is typically found in laptops. The SSD cards are wider (29.85mm) than the M.2 cards (22mm) and tend to have 2 holes at the edges for bolting down whereas a M.2 card has a half a hole on the edge opposite the connector (in the middle) for bolting down.
M.2 SATA uses an M.2 connector with SATA interface. M.2 SATA SSDs are B+M-keyed and can fit in sockets for B-keyed and M-keyed connectors, but will not function if the connector interface is PCIe. There is information on keys in the M.2 section.
PCI Express SSD Cards tend to fit in the x4 (most SSD cards) or the x8 PCI Express slot. There are currently 4 versions PCI Express available, with PCI Express 3.0 being the one most common in current motherboards. The most common slots for PCI Express 3.0 are Pcie x1 8Gb/s, Pcie x4 32 Gb/s, Pcie x8 64Gb/s, and Pcie x16 128Gb/s. Pcie x1 is a slot with 1 lane, Pcie x4 is a slot with 4 lanes, etc.
M.2 PCIe uses an M.2 connector which uses 4 lanes of the PCI Express. The M.2 SSD is plugged directly into the M.2 connector and bolted down. M.2 modules can vary in length and width. The majority of M.2 SSDs are 22mm wide, but can vary in length. They can be 30mm., 42mm., 60mm., 80mm., and 110mm. Most common are 42mm and 80mm long. Typical number notation for M.2 SSDs are width+length, so a 2242 is 22mm wide and 42mm long and 2280 is 22mm wide and 80mm long. M.2 modules can have several different keys/notches, but the 3 that are important for SSDs are B, M or B+M. This is very important since they must match your connector. B has a gap on the right side followed by 6 pins. M has 5 pins on the left followed by a gap. B+M has 5 pins on the left followed by a gap then a bunch of pins then a gap on the right side followed by 6 pins. M.2 SSDs can be problematic, so be sure to read your motherboard manual carefully be make sure the SSD you purchase is compatible in interface, length and key type. M.2 NVMe SSDs for PCIe 3.0 x4 lane are M-keyed.
A
U.2 connector uses 4 lanes of the PCI Express. The U.2 SSD is plugged into the U.2 connector via a cable. U.2 connectors are rare on mainstream motherboards, tending to reside in server motherboards. U.2 SSDs can be added to motherboards without U.2 connectors via adaptors that can plug into a M.2 connector.
There are two common host controller interface and storage protocols/standards for the transfer of data. The
Advanced Host Controller Interface (AHCI) was designed for Hard Drives and works fine for SATA SSDs, but is too slow for the faster PCI Express SSDs.
NVMe (non-volatile memory express) was designed to be used with SSDs and can access multiple memory chips on an SSD or multiple SSDs at the same time. NVMe solid-state disks can handle 65536 parallel I/O requests compared with only 32 I/O requests processible by SATA 3.0. You switch on AHCI or NVMe via the motherboard.
There are two types of memory used for SSDs, flash memory and 3D XPoint. Here are 3 types of
2D NAND flash memory.
Single-level cell (SLC) stores 1 bit per cell and offers the highest endurance. SLC can be ten times more expensive to manufacture than MLC.
Multi-level cell (MLC) stores multiple bits per cell, though in actuality this usually means 2 bits per cell. MLC provides higher storage capacity, but lower endurance than SLC. When run in single bit mode to mimic SLC (called Pseudo-SLC, pSLC, MLC+), it can have increased endurance, reduced error rates and better SSD longevity over SLC.
Triple-level cell (TLC): Stores 3 bits per cell and provides higher storage capacity, but offers lower endurance than SLC and MLC.
3D NAND is when you stack the 2D NAND on top of each other like floors in a Skyscrapper. Each floor is referred to as a layer, ie. 64-layer 3D NAND. 3D NAND when compared to 2D NAND, has a lower cost per gigabyte, reduces power consumption, has a longer life span, has higher reliability, and possibly a higher data write performance, but at a higher manufacturing cost.
Optane Memory shuttles data between the RAM and the SATA devices (SSDs, hard drives) storing often used data on it's small (16GB to 1.5 TB) but extremely fast
3D XPoint non-volatile memory. The computer sees the optane SSD and the SATA device it is accelerating as a single device.