How to Use Pendrive as RAM in Windows [Complete Guide]

If your Windows computer feels slow while opening programs, switching between applications, or browsing the web, you may wonder whether you can use a USB flash drive (pendrive) as additional RAM. The good news is that Windows includes a feature called ReadyBoost, which allows compatible USB drives to work as extra cache memory. While it does not physically increase your computer’s installed RAM, it can improve performance on some older systems, especially those with traditional hard disk drives (HDDs).

It is important to understand that ReadyBoost is not the same as installing more RAM. A USB drive cannot replace physical memory. Instead, it stores frequently used data to help Windows access it more quickly. On computers with Solid State Drives (SSDs) and 8 GB or more of RAM, ReadyBoost usually provides little or no noticeable improvement because SSDs are already much faster than USB flash drives.

In this very important and useful guide, I’ve explained everything you need to know about using a pendrive as RAM in Windows, including the requirements, setup process, and important limitations.

How to Use a Pendrive as RAM in Windows [Full Guide]

Before you begin, make sure you have a USB 3.0 or USB 3.1 pendrive with at least 8 GB of free space. For better results, using a 16 GB or larger flash drive is recommended.

Also, ensure that the drive does not contain important files because you may need to format it during the setup process.

Step 1: Check Whether Your Computer Can Benefit from ReadyBoost

The first thing you should do is determine whether your computer is a good candidate for ReadyBoost. This feature was mainly designed for older Windows computers that use mechanical hard drives (HDDs) and have a limited amount of RAM.

If your computer already has an SSD and 8 GB or more RAM, Windows may disable ReadyBoost automatically because it recognizes that your storage device is already fast enough. In this situation, using a USB drive as cache memory will not provide meaningful performance improvements.

To check your storage type, open Task Manager by pressing Ctrl + Shift + Esc. Select the Performance tab and click Disk. Windows will show whether your primary drive is an HDD or SSD.

If your system uses an HDD and has only 2 GB to 4 GB of RAM, ReadyBoost may help reduce delays when opening frequently used applications.

Step 2: Choose the Right Pendrive

Not every USB flash drive is suitable for ReadyBoost. Older and slower drives may fail the performance test performed by Windows.

Choose a reliable USB drive with fast read and write speeds. A USB 3.0 flash drive connected to a USB 3.0 port usually delivers the best performance. Although USB 2.0 drives can work, they are generally much slower.

Avoid using a pendrive that already contains important documents, photos, or videos because ReadyBoost reserves a significant amount of space for its cache file. Keeping the drive dedicated to ReadyBoost often provides better results.

Step 3: Connect the Pendrive to Your Computer

Insert the USB flash drive into an available USB port on your computer.

Wait a few moments while Windows detects the device. You should hear the connection sound and see the drive appear in File Explorer.

If Windows displays an AutoPlay window, you can simply close it because the ReadyBoost settings will be accessed through the drive’s properties.

Step 4: Format the USB Drive if Necessary

Sometimes a USB drive contains file system errors or uses an unsupported format. Formatting it before enabling ReadyBoost helps ensure better compatibility.

Open File Explorer and locate your USB drive. Next, right-click the drive and select Format.

Choose NTFS or exFAT as the file system. Leave the allocation unit size at its default setting.

Click Start and wait until the formatting process finishes.

Remember that formatting removes all existing data from the drive, so make sure you have backed up any important files beforehand.

Step 5: Open the ReadyBoost Settings

Once the USB drive is ready, open File Explorer again.

Locate your pendrive and right-click it.

Choose Properties from the menu.

In the Properties window, click the ReadyBoost tab.

If your USB drive passes Windows performance testing, you will see several ReadyBoost options available.

If the ReadyBoost tab does not appear, your computer or USB drive may not support the feature, or Windows has determined that it would not improve system performance.

Step 6: Enable ReadyBoost

Inside the ReadyBoost tab, you will see several options.

Select Use this device.

Windows will automatically recommend an appropriate amount of space to reserve for ReadyBoost. You can accept the recommended value or manually adjust it using the slider.

In most situations, allowing Windows to use the recommended amount works best because the operating system calculates the optimal cache size.

After selecting the desired amount of storage, click Apply, followed by OK.

Windows will create a hidden cache file named ReadyBoost.sfcache on the USB drive.

Step 7: Restart Your Computer

Although ReadyBoost starts working immediately after activation, restarting your computer ensures that Windows fully initializes the cache.

Close all open applications and restart your PC.

After Windows loads again, continue using your computer normally. Over time, Windows learns which files and applications you use most often and stores them in the ReadyBoost cache for quicker access.

Performance improvements usually become more noticeable after several days of regular use rather than immediately after setup.

Step 8: Verify That ReadyBoost Is Working

To confirm that ReadyBoost is active, open the USB drive properties once again.

Go to the ReadyBoost tab.

If Use this device remains selected and Windows displays the reserved storage amount, ReadyBoost is functioning correctly.

You may also notice the hidden ReadyBoost.sfcache file on the drive if hidden files are enabled in File Explorer.

Avoid deleting this file manually because Windows manages it automatically.

Step 9: Safely Remove or Disable ReadyBoost

If you no longer wish to use your pendrive for ReadyBoost, open the drive’s Properties window again.

Navigate to the ReadyBoost tab. Now, select Do not use this device. Click Apply and then OK.

Windows will remove the cache file and restore the reserved storage space.

You can now safely use the USB drive for normal file storage again.

Common Reasons ReadyBoost Does Not Work

Many users become confused when Windows refuses to enable ReadyBoost. In most cases, this happens for one of several common reasons.

Your computer may already have an SSD, making ReadyBoost unnecessary.
The USB drive may not meet Microsoft’s minimum speed requirements.

The flash drive may not have enough free storage available.
The drive may contain errors that require formatting.

Windows may have determined that your system already has enough RAM, making ReadyBoost unnecessary.

Checking each of these possibilities usually helps identify why the feature is unavailable.

FAQs

Can a pendrive actually become RAM?

No. A USB flash drive cannot become real physical RAM. ReadyBoost simply uses the drive as a fast cache to reduce hard drive access times.

Does ReadyBoost increase installed RAM?

No. Your installed RAM remains exactly the same. ReadyBoost only improves how Windows stores and retrieves certain cached data.

Does ReadyBoost work on Windows 11?

Yes. ReadyBoost is still available in Windows 11, but many modern computers with SSDs will not benefit from it.

Is ReadyBoost useful on SSD computers?

Usually no. SSDs are significantly faster than USB flash drives, so ReadyBoost often provides no measurable improvement.

How much USB space should I allocate?

Windows normally recommends an appropriate amount automatically. Using between 8 GB and 32 GB is common for compatible systems.

Can I use multiple USB drives for ReadyBoost?

Yes. Windows supports multiple ReadyBoost devices, although the total benefit depends on your system configuration.

Will ReadyBoost make games run faster?

Generally no. Modern games rely primarily on the processor, graphics card, and installed RAM. ReadyBoost mainly helps with loading frequently accessed files on older HDD-based systems.