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SanDisk Extreme v2 Portable SSD Review: Twice the Speed, Better Security

Integrating WD’s Blue SN550E and leveraging BiCS4 TLC flash, the SanDisk Extreme offers responsive performance in a secure and portable package.

SanDisk Extreme v2
Editor's Choice
(Image: © Tom's Hardware)

SanDisk’s Extreme v2 is a durably designed and strong-performing portable NVMe SSD for content creators and travelers who are constantly on the move. No matter the trek, the Extreme v2 should work by your side without fault time and time again.

(Image credit: Tom's Hardware)

There is a capacity for almost anyone’s need, and the drive with solid improvements over the original--although it still lacks a power indicator. We are especially pleased with the secure password protection, now backed by a hardware-accelerated AES 256-bit encryption engine for much better performance. The SanDisk Extreme v2 performed flawlessly throughout testing, displaying solid results all around, and delivered especially good sustained write speeds.

Unlike the Samsung T7/T7 Touch, Crucial X8, and WD My Passport SSD, the Extreme v2 carries an IP rating, ensuring your data remains safe, even in wet or dusty environments. This is also handy for those like me who forget that they’ve left their drive in their pants pocket and it cycles its way through the clothes washer/dryer.

Each capacity comes priced fairly, matching the cost of the Samsung T7, but offering a better value in our opinion. Crucial’s X8 and WD My Passport SSD may be $10 cheaper, but when it comes to consistency, the Extreme Pro is more robust and won’t degrade to such slow write speeds after filling the cache, making it easily worth the few extra dollars. Also, SanDisk’s latest drive is roughly $120 cheaper than the LaCie Rugged SSD. The Extreme v2 offers up a compelling value for those in search of a reliable and performant portable storage solution.

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Sean Webster
Sean Webster

Sean is a Contributing Editor at Tom’s Hardware US, covering storage hardware.

  • Co BIY
    How often does an external SSD drive need to be powered up or plugged in to maintain the data ?

    Does flash data have a half-life ?
    Reply
  • deesider
    Co BIY said:
    How often does an external SSD drive need to be powered up or plugged in to maintain the data ?

    Does flash data have a half-life ?
    It seems that the most often quoted retention time is 10 years.

    There is an Anandtech article that discusses findings that a worn out drive (at the end of its endurance rating) can lose data much faster depending on temperature: https://www.anandtech.com/show/9248/the-truth-about-ssd-data-retention
    Reply
  • Uiflorin
    Flash memory stores the information as electric charge (electrons for negative charge, or lack of electrons for positive charge) in a buried and insulated (in oxide) gate of a mosfet transistor. Once this charge is transferred into that gate, it can stay there for a period of time expressed in years, or tens of years, and it can still be read correctly as 1 or 0. This is called RETENTION time. After that period, the charge wil statistically leak out and be insuficient for that bit of information to be read correctly. Depending on the technology, a bit of information is stored as no charge (logic level 1, or bit 1), while the other (logic level 0, or bit 0) as charge present in the transistor, so after the retention time only the logic level 1 will be ready correctly, because there was no charge to leak out. Anyways, that's irrelevant, if some of the 0 bits are not read, the information is lost. For flash memory this time is 10 years as guarantied retention time, for eeprom is 100 years in normal storage conditions. Temperature affects the retention, higher temperature leads to higher leakage of charge from that insulated gate, so better keep the flash cards cool.

    Now, to answer your question, powering up the drive containing that memory does not refresh it's content. You can keep it powered up continuously, the information stored in the transistors is NOT UPDATED OR REFRESHED by the power applied to device, unless you write again the information. This principle of refreshing the data from time to time is used in the RAM memory in computers, and losing power leads to losing data.
    Hard drives based on magnetic retention of data are better in this respect, since the retention time is greater if the device is kept properly.

    Another thing about the flash memory is the indurance of the cell, how many times the memory cell accepts write/erase cycles until it starts to "wear" and not store anymore the information. That number is in the hundreds now days. If you read correctly the specification of an SSD drive, you will find a specification called "TBW", total bytes written. Dividing that number by the capacity of the drives yields the number of erase/write cycles that will wear the cells.

    Flash memory based drives have now implemented a special "wear" algorithm, such that new data is written on cells that are not progammed with data, and so files are moved continuosly across the drive to mentain a balance of erase/program for all the cells, otherwise if a file is continuously written and modified on the same memory cells, these will wear after those few hundred of cycles and not be able to be used anymore. That is why a worn out SSD drive, that has reached a TBW spec, will not retain the information for long.
    Reply
  • Co BIY
    Uiflorin said:
    Now, to answer your question, powering up the drive containing that memory does not refresh it's content. You can keep it powered up continuously, the information stored in the transistors is NOT UPDATED OR REFRESHED by the power applied to device, unless you write again the information. This principle of refreshing the data from time to time is used in the RAM memory in computers, and losing power leads to losing data.

    Interesting. I assumed that "refreshing" the charges/data was one of the routine maintenance tasks of the SSD controller and assumed that it would be done on a routine/scheduled basis. If the data is stable for 10 years then it makes sense that this is not done. I assumed the stable time was a lot less then 10 years.

    It seems like "refreshing" the charges should be a maintenance function of devices.
    Reply
  • deesider
    Co BIY said:
    Interesting. I assumed that "refreshing" the charges/data was one of the routine maintenance tasks of the SSD controller and assumed that it would be done on a routine/scheduled basis. If the data is stable for 10 years then it makes sense that this is not done. I assumed the stable time was a lot less then 10 years.

    It seems like "refreshing" the charges should be a maintenance function of devices.
    I have a feeling that the wear-leveling algorithms will take care of that if the drive in still in use. So even data that is never changed or moved by the user will be refreshed by moving it to different cells to ensure even wear of all cells across the drive. Otherwise old data would be hogging the nice and shiny, barely used cells, leaving the sometimes empty cells to wear down and brick the drive.
    Reply
  • Co BIY
    A question that I think needs answered authoritatively by the device manufacturers is:

    If I back up important archive data to an SSD and then disconnect it and place it in a box on a shelf in normal storage conditions, Then how long will my data remain in perfect condition?

    Will that time be extended by plugging it in and powering up every year or so ?
    Reply