The 10 Best Solid State Drives
10. Samsung 860 Evo SATA
- max capacity of 2 terabytes
- less expensive than similar models
- no faster than a standard sata drive
|Rating||4.1 / 5.0|
9. Adata SE730H
- uses the latest usb-c standard
- speeds up to 500 gigabytes per sec
- pricier than non-rugged units
|Rating||3.6 / 5.0|
8. XPG Gammix
- advanced layered flash memory
- has a fixed heat sink
- inconsistent speed and reliability
|Rating||3.6 / 5.0|
7. Samsung Pro
- consistent performance at all temps
- twice the lifespan of most others
- not intended for home consumers
|Rating||3.8 / 5.0|
6. Western Digital Blue
- great value for a 1-terabyte drive
- laptop-ready 7-millimeter profile
- not the highest performing model
|Rating||4.2 / 5.0|
5. My Passport
- especially thin and light
- inexpensive for a portable option
- a bit slower than the competition
|Rating||4.4 / 5.0|
4. Samsung 860 Evo
- ultra-fast sequential write speeds
- longer lifespan than prior models
- limited by overall bus speed
|Rating||4.4 / 5.0|
3. Samsung T5
- built-in 256-bit hardware encryption
- not much bigger than a credit card
- rugged all-metal body
|Rating||4.7 / 5.0|
2. 970 Evo
- leads the pack in tests
- integrated sensor-controlled cooling
- lasts a minimum of 600 full rewrites
|Rating||4.7 / 5.0|
1. Crucial MX500
- excellent real-world speeds
- up to 2 terabytes of space
- great for all new operating systems
|Rating||4.9 / 5.0|
Understanding How A Computer's Memory Works
In the most basic sense, a computer's memory has three parts: cache, the memory, and the hard disk. Each one of these parts performs a specific function.
The cache, which is the innermost memory unit, performs the calculations and procedures of your computer as it operates. It is a component of the high-speed static RAM, also known as SRAM. The majority of programs a computer uses access the same data again and again, storing this data in the SRAM allows the computer to access this information as quickly as possible, without having to access the DRAM, which is slightly slower.
This makes a computer more efficient when running commonly used programs. The electrical pathways to the cache are shorter than the pathways to the memory or the hard disk, making data available nearly instantaneously.
The memory, most often referred to as RAM, is where a computer stores information that is related to processes and programs that are currently active. RAM storage is temporary and it is only stored while a computer is powered on. It helps a computer run memory-extensive programs more quickly by temporarily transferring that programs information from the hard disk to the RAM. RAM can achieve speeds exceeding 15,000mbps, making accessing information on it much faster than accessing memory on a standard hard drive, which can reach speeds somewhere in the area of 1,000mbps.
All other information on a computer is stored in the hard drive, including program data, files, images, settings, etc. In order to access this information, a computer must first load it from the hard drive to the RAM, which makes the process take longer. The cache and RAM operate in nanoseconds, while the hard drive operates in milliseconds.
With traditional hard disk drives, the computer has to wait for the hard drive to spin and its arm to locate the exact place on the disk to access the memory needed before it can be transferred to the RAM. A solid state drive has no moving parts and can access the necessary data 10 times quicker than a spinning hard disk drive.
Why Solid State Drives Are Faster Than Hard Disk Drives
Hard disk drives (HDD) store their data on a series of spinning magnetic disks. To access or add information onto one of these drives, an actuator arm has to move into position over the correct spot on the disk. It works in a very similar manner to a record player. This causes a significant wait time when accessing or writing data on a hard disk drive.
Not only must the computer wait for the disk to spin into the proper position, but sometimes data is stored in multiple locations, which takes even more time to access because the actuator has to move from place to place. If a drive is in sleep mode, it takes additional time for it to spin up to full speed. On average, it takes from 10 to 15 milliseconds for a traditional hard disk drive to find data and begin accessing it.
Solid state drives (SSD) have no moving parts, hence the name solid state. Data on solid state drives is saved to a pool of NAND flash memory, which is comprised of floating gate transistors. These are different than the transistors in DRAM, which need to be refreshed multiple times per second and only store memory when powered on.
NAND flash memory is non-volatile and can store data whether it is powered on or not as it always retains its charged state. Because solid state drives have no moving parts, there is no lag time while a computer waits for the disk to spin and the actuator arm to locate the data on the disc. This allows a computer to work faster and access needed data quicker. An SSD is still slower than cache and DRAM, but easily outpaces hard disk drives.
Drawbacks Of Solid State Drives
Solid state drives are able to access data faster than hard disk drives, and when new can also write data faster, but overtime SSDs will slow down. This is because of the processes an SSD must perform before it can write to a drive. In an HDD, data can be written to any location, at any time, even if there is already data there. SSDs aren't able to overwrite data directly. They can only write data to empty page blocks. If there is no empty page blocks, the SSD must create one by deleting data before it can write new data.
SSDs read and write data at the page level, but can only erase data at the block level. This is because it requires too much voltage to erase data at the page level and it can stress the individual cells around the page cells being rewritten. For an SSD to write data onto a previously used page, it must copy all of a block's contents and save it to memory. Then it deletes the entire block, and rewrites the entire block data along with the updated page.
This is why SSDs start off being able to write data much faster than HDDs, but over time slow in performance. New SSDs are filled with empty, or mostly empty pages, but as they are used the pages and blocks begin to get filled up. Luckily there are steps you can take to increase the lifespan of your SSD's top speeds.