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Why Are Flash Drives Slower Than SSDs?

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Flash drives and solid state drives are similar in a few ways. Both are solid-state memory devices used for storage, and both use the NAND flash technology to function. However, they also have significant differences, including flash drives being slower than SSDs.

Flash drivers are slower because they use lower-quality MLC flash memory. Meanwhile, SSDs use faster SLC memory. Additionally, SSDs use allocation algorithms and parallelism for a faster transfer rate. The interfaces also make a difference, since SSDs use SATA ports while flash drives use USB.

If you want to know more, stick around! I will explain all the reasons why flash drives are slower than SSDs, and show you additional ways in which these two devices are different. I will also include a guide to help you decide when to use one or the other.

5 Reasons SSDs Are Faster Than Flash Drives

Given that both SSDs and flash drives use the same NAND technology, you might assume that both have more or less the same speed. However, several factors make SSDs much faster than flash drives.

1. SSDs use parallelism

SSDs have a more complex architecture than flash drives. Their internal structure is made of several flash memory devices connected through different channels to flash memory controllers. As a result, SSDs can access all these devices in parallel to transfer data much faster.

2. SSDs use SATA

Typically, you use a USB type A (or USB-C, micro-USB) to connect a flash drive to your computer. Meanwhile, you usually use SATA ports to connect an internal SSD, ideally SATA 3. SATA ports are much faster and more efficient than USB ports.

3. SSDs use higher-quality flash memory.

Generally, flash drives use lower-quality flash memory because it’s cheaper. As a result, it takes longer to read and write on them. SSDs, on the other hand, use higher-quality flash memory than flash drives, which is reflected in their prices.

4. SSDs use allocation algorithms

SSDs use data allocation algorithms for wear leveling, which distributes writing on all blocks of the SSD in an even way to avoid wearing out the blocks. These algorithms ensure cells are pre-erased and ready to be written on, making your SSD faster.

5. SSDs use single-level cell technology

Flash drives use Multi-Level Cell (MLC) memory, which stores two bits of information in each cell. As a result, these devices have lower transfer speeds and shorter lifespans. Most SSDs use Single-Level Cell (SLC) memory, storing one bit in each cell. As a result, the data is written faster, leading to higher transfer speed and better endurance.

Other Advantages of SSDs Over Flash Drives

Speed is the most significant reason SSDs are superior to flash drives. However, there are other factors where you can see the difference in performance between the two devices. 

Even if speed is not one of your concerns, you may be convinced one way or the other once you review the differences below: 

  • Higher capacity. Flash drives have a limited capacity for storing information, with their maximum capacity at around 1TB. SSDs, on the other hand, can store much more information, easily exceeding 2 TB. SSDs for computers can reach a capacity of 30.72 TB.
  • Lower power consumption. A major advantage of SSDs is that they consume significantly less energy than flash drives. Their speed and efficiency are key factors that help SSDs use far less power. The difference is noticeable in laptops, where SSDs contribute to better battery health because of low power consumption.
  • Better durability. As mentioned above, flash drives use lower-quality technologies and materials to keep costs low. Consequently, these factors contribute to a shorter lifespan. SSDs are made of more expensive materials and use technologies that improve their performance and increase their endurance. SSDs have better durability as a result.

Disadvantages of SSDs

From what I’ve explained so far, you can conclude that SSDs are faster, more durable, and more efficient than flash drives. However, there are certain areas in which flash drives are better than SSDs:

  • Flash drives are cheaper than SSDs. The low-quality materials and technology may reduce their performance but simultaneously allow them to be much more affordable than SSDs.
  • Flash drives are portable. If your computer has a problem, you can easily remove a flash drive and connect it to another computer. The process is much more complicated for SSDs.
  • It’s easier to retrieve lost data from flash drives. Retrieving data from SSDs is more complex and requires a deeper scan.

When To Use Flash Drives Instead of SSDs

Flash drives and SSDs are both storage devices, but you can use them for different purposes. 

SSDs are used for faster boot-up processes and data transfers. Flash drives are used to move data from one computer to another easily. Flash drives can’t replace internal SSDs in any way because they don’t have the capacity or speed, as I explained above.

However, there are external SSDs that have more or less the same function as flash drives. They are externally connected to your computer via USB 3 ports. They are faster and have a much bigger capacity than flash drives.

If you’re looking for a simple and quick device to move a small amount of data, choose a flash drive—it will cost less and still work perfectly. If you want more space for storage and are willing to spend more for a more durable device, choose an SSD.


Both flash drives and SSDs rely on NAND flash technology. However, the two storage devices have major differences. Flash drives are slower because they use lower-quality flash memory and have MLC memory, which makes them transfer data at a slower rate and less efficiently. Moreover, the allocation algorithms and SATA ports that SSDs use contribute to their higher speed.

SSDs also have more storage capacity and consume less energy. Additionally, they tend to be more durable than flash drives. Understandably, these differences are reflected in the prices of these devices, as flash drives are much cheaper than SSDs.

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