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Windows Forums member, shoby, asked the following question in our suggestion box:

I would like to see a review about Ready Boost in Windows 7.
Does it really help you out when you need some extra performance or does it just look like it helps you out ?

It surely can’t be like you actually went out and bought some RAM, but how good is Ready Boost actually.
Is it gonna help me out with the my daily tasks/multitasking.

This guide answers these questions and offer suggestions to help you get the most out or ReadyBoost or the most out of the money you’d spend on a flash drive with which to use ReadyBoost. Specifically, we’ll cover the following:

  • What is ReadyBoost?
  • Does ReadyBoost really work?
  • What are the requirements for ReadyBoost?
  • What security risks does ReadyBoost pose?
  • What alternatives are there to ReadyBoost?

If you want to learn how to use ReadyBoost, see this guide: Speed up Windows with ReadyBoost.

What is ReadyBoost?

To get a clear explanation of ReadyBoost I went to the Windows 7 help console (yeah, I’m not playing with you, I really did) and got the following:

ReadyBoost can speed up your computer by using storage space on most USB flash drives and flash memory cards. When you plug a ReadyBoost-compatible storage device into your computer, the AutoPlay dialog box offers you the option to speed up your computer using ReadyBoost. If you select this option, you can choose how much memory on the device to use for this purpose.

To add to this, ready boost stores frequently used data on a flash drive, which typically reads much more quickly than it would from your hard drive. We’ll stick with these explanations now and expound on them in the next section.

Does ReadyBoost Really Work?

In theory, yes. But not for every setup.

In this section, we’ll explore the technical details of ReadyBoost and look at some benchmark tests to help you determine whether ReadyBoost will help you.

The Technical Part

The average random 4K read from a flash device is approximately ten times faster than accessing the same information from your 7200 rpm hard disk drive. As thumb drives can be read very quickly (and even more quickly as we adopt USB 3.0, this makes them a great candidate for storing information that has to be accessed as quickly as possible.) The reason it’s an average time is because there is little to no seek time on a flash drive whereas a disk drive has different seek times depending on how contiguous the data is and how much is being read.

All flash drives are not made equal (ever wonder why some “brand name” drives are 3-4 times the price of ones you can find on eBay?) To work with ReadyBoost, the flash drive must be capable of 2.5MB/sec throughput for 4K random reads and 1.75MB/sec for random writes. How do you know if your current drive is compatible? Plug it in and see if Windows offers the use of ReadyBoost. What about a new drive? Check the next section for the answer to that question.

Benchmark Testing

As I don’t have the equipment to test ReadyBoost, I’ll summarize some data from Tom’s Hardware and suggest you head to the test results article to get a full insight of the effects of ReadyBoost.

This chart shows the time it takes to open Microsoft Outlook 2007 on a machine with 512MB RAM. Each line represents the first, second, and third opening of the program through three cycles (for a total of nine times.)

As you can see, the more you use ReadyBoost, the more it helps you as it collects information to help you get the most out of the space you allocate for it.

The effects of ReadyBoost are lessened by having more memory.

To see more about this data, view the original chart.

To summarize the results from the Tom’s Hardware tests, ReadyBoost is only really good if you have an older, slower system. You may be wasting a good flash drive if you use it on a more powerful machine.

So, Does ReadyBoost Really Work?

The effect of ReadyBoost will be greater if you are on a PC that is currently struggling to keep up with everything you throw at it. Typically, a struggling machine (that’s not infected with malware) has low available memory and runs slow because your hard disk is being thrashed with inputs and outputs (IO) of data the operating system needs available (should be stored in RAM) and historical data used to speed up routine processes (Superfetch.)

In other words, if your PC has 512MB of RAM then you’re going to see a big improvement using ReadyBoost. However, you’ll see an even greater improvement by adding more RAM, which for another 512 MB / 1GB can be about the same price as a good quality 4GB flash drive. I’d go with the extra memory (more about that later.)

What are the Requirements for ReadyBoost?

If you’ve decided to use ReadyBoost, the requirements are:

  • A PC:
    • With a free USB 2.0 port (or up to eight for Windows 7 64-bit.)
    • Running Windows Vista or Windows 7.
  • A flash drive:
    • Capable of 2.5MB/sec throughput for 4K random reads and 1.75MB/sec for random writes.
    • Between 250MB and 4GB in size (Vista 32-bit.)
    • Between 250MB and 16GB in size (Vista 64-bit.)
    • Between 250MB and 4GB in size (Windows 7 32-bit.)
    • Between 250MB and 32GB in size and up to eight devices for a total of 256GB (Windows 7 64-bit.)

If you want to learn how to use ReadyBoost, see this guide: Speed up Windows with ReadyBoost.

Microsoft offer the following tips for ReadyBoost:

Here are some tips on what to look for when selecting a USB flash drive or flash memory card to use with ReadyBoost:

  • The minimum amount of available space recommended for ReadyBoost to effectively speed up your computer is 1 GB.
  • For best results, use a flash drive or flash memory card with available space of at least double the amount of memory (RAM) in your computer, and preferably four times as much memory. For example, if your computer has 1 GB of RAM and you plug in a 4 GB USB flash drive, set aside at least 2 GB on the flash drive to get the best performance gain from ReadyBoost, and preferably the entire 4 GB. How much memory you need depends on how you use your computer. Keeping a lot of programs open at once uses more memory.
  • Give ReadyBoost 2 GB to 4 GB of space for best results on most computers. You can reserve more than 4 GB of space for ReadyBoost on most flash drives and flash memory cards. (Storage devices formatted with the older FAT32 file system can’t store more than 4 GB.) You can use a maximum of 32 GB of available space on any single removable storage device with ReadyBoost and up to 256 GB total per computer (by inserting up to eight USB flash drives or flash memory cards into the same computer).
  • To work with ReadyBoost, a USB flash drive must support USB 2.0 or higher. Your computer must have at least one free USB 2.0port where you can plug in the flash drive. ReadyBoost works best if you plug the flash drive into a USB port directly on the computer, rather than into an external USB hub shared with other USB devices.
  • If you want to be sure a USB flash drive works with ReadyBoost, look for a note from the manufacturer that the flash drive is “Enhanced for ReadyBoost.” Not all manufacturers list this on their packaging. If there is no mention of ReadyBoost compatibility, the flash drive still may work with ReadyBoost.
  • There are many different kinds of flash memory cards, such as CompactFlash and Secure Digital (SD) memory cards. Most memory cards work with ReadyBoost. Some SD memory cards don’t work well with ReadyBoost due to issues with the SD card interface. ReadyBoost will display an error message if you attempt to use one of these cards.

What Security Risks Does ReadyBoost Pose?

Surely carrying around a thumb drive that contains information on what you’re doing on your machine could pose a security risk in the wrong hands? Hopefully not because Microsoft use AES-128 to encrypt all data that’s written to the ReadyBoost cache, so the chances of exposing sensitive date are small.

What Alternatives are there to ReadyBoost?

Two alternatives (that will significantly improve performance over ReadyBoost) are:

  • Using a Solid State Drive (SSD) for your Operating System Drive.
  • Adding additional memory (RAM) to your computer.

If your budget is less of a concern to you and if you already have 4+ GB RAM, using one or both of these options will be more beneficial to the overall performance of your computer.

Alternatively, you can accept that you have a pretty good PC and don’t need so spend more hard-earned money on it. But who am I kidding, most of us here are geeks at heart, right?

Does ReadyBoost Work for You?

Let us know your system specifications in the comments and tell us if ReadyBoost made a difference for your machine. Under what loads do you put your machine? i.e. Photoshop, Office, programming IDEs, video editing etc.

About Rich

Rich is the owner and creator of Windows Guides; he spends his time breaking things on his PC so he can write how-to guides to fix the problems he creates.

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  • shoby

    Thank you Rich for answering my question. It helped me out.

  • Anonymous

    There are three main reasons that computer slows down: registry errors, spyware and adware, viruses. Actually, however, according to the statistics, 90% of computer problems are caused by computer registry, so it is important to constantly clean up your computer registry to ensure that your computer runs in a good condition. Now there are two good software on the Internet: Tuneup360 and Norton systemwork, but the latter one is a little bit difficult. For the beginners, Tuneup360 is a good choice.

    • Jeremy Collake

      Sorry, but this is not true. It is a myth perpetrated by the Registry Cleaning industry. Registry ‘errors’ do not cause any performance degradation. 

      The typical belief is that excessive registry keys can cause a slowdown, but this is simply false. Your registry has hundreds of thousands of keys, indexed using efficient data tries. In testing using RegBench, no tested registry cleaner was able to make a difference. The ONLY thing that worked as a full rebuild of the registry hives to reduce internal (e.g.  not disk) fragmentation and inefficient storage within the hives.

      A common response is, well, maybe some registry ‘errors’ such as invalid file links can cause slowdowns. This has never been demonstrated to be true, and it is very difficult to even come up with any plausible scenario where it would be true. Further, rarely do registry cleaners even address keys where this could be true.

      Worst is that Registry Cleaners often cause accidental damage. Read: http://bitsum.com/registry_cleaner_fix.php

      • Stu

        Finally someone else in the same boat! I couldn’t have said it better myself.
        How would one go about rebuilding the hives? I assume it would have to be on a vanilla install?

      • beermatt

        I think the point is it’s not worth investigating.  I haven’t reinstalled my OS (XP) for about 6 years now and my Start menu covers 4 full columns at 1920×1080!  Performance compared to a fresh install?  Hardly anything.

        The amount of rubbish I’ve installed & uninstalled over the years (I play a lot!) I should have bazillions of these “registry errors” but don’t.  There’s probably some rubbish in there but it doesn’t cause a problem.  If your computer’s running slow, look elsewhere.

      • cpguru21

        Well said Jeremy.  For any one interested, there is registry defrag product by AUSLogics, which works, however I never noticed a difference in performance as Jeremy pointed out here.

  • Gphoto45

    My one laptop, which is basically my kick-around one, is a Toshiba M45. As such, the max ram it can handle is 2 gig. (Yep, tried 2.5,3,4, etc. I am running Win7, so using the card reader was out of the question, as the TI xx21 is not recognized by Win7. Enter the 32 bit cardbus with a SDHC adapter! Works great! My times are increase slightly over the graph specs in the article, and I am testing it with 4 gig, 6 gig, and 8 gig SDHC cards. Amazingly enough, I got better performance with 6 gig RB than I did 4 or 8 gig, using a Patriot USB 2 stick, Not sure why. Main reason for going to the SDHC card is simply so I can leave it safely in the laptop, while moving it around. Just my results from testing, and great article, Rich! No laptops were injured during the testing of this product!

  • Bonnie Joethomas

    readyboost is has helped me to speed up my netbook….i really think readyboost has a good application in case of netbooks….

  • Nik74

    Readyboost really helped with loading Windows Live Mail (a diferennce of almost 30 seconds if i open chrome too) at at start up, additionally my computer is much more responsive and stable.

    2GHz processor, 5400rpm HDD, 4Gb Ram

  • Noshitonline

    you will see no improvement with that CPU and 8GB ram

  • Jakubinscott

    WHats up homes btw   redyboost is toast on my pc how do i fix it?

  • Conway220

    if i got an external hard drive of 500 GB and used it for redyboost, would my computer become epic?  Please email the answer to me at

    • Rich

      It would not. The drive will probably not perform fast enough to be ready boost eligible.

  • 6716

    Im running 2.4 ghz Dual Core processor and 2 Gb of RAM. Will ReadyBosst give me better performance?

  • MoolaMails

    I am looking for an upgrade, I have a netbook, 2 gb ram with an intel atom 1.66 ghz processor. Will I get a speed boost or longer battery life?

  • Anonymous

    Confused! :~

    At this site http://www.ehow.com/how_4431896_use-flash-drive-as-ram.html, at point 6 clearly states that if you have already a 2GB of RAM you better not try to get more RAM and that some systems max out at 4GB…this could damage your pc, it says!

    My machine has an Intel(R) Core2 Duo CPU processor – 1.50GHz and an installed RAM of 2GB, running a 32-bit WIN 7 OS. Getting a 4GB+ would it help and, most importantly, will it not damage the machine? 

    • Rich

      No damage is possible. ReadyBoost is not a replacement for RAM but it’s a compliment for systems with lower memory. Give it a try and see if it speeds your system up. Good luck!

  • Rich

    It can be undone. The easiest way is to format your drive when you’re done trying ReadyBoost.

  • Alif Rio Utama

    it work for me when i m using after effect. faster render progress, on my intel i3 2 gb memory and 4gb flashdrive (readybost)

  • Ankit

    Hi rich, could you Please tell how to see the net RAM in PC after Ready boost …..reply me at

  • Pika the Nord

    hi i have an hp pavilion with 2gb of ram and 512mb graphics memory. It has an intel dual core @ 2.0 ghz, and i am running skyrim- will the readyboost benefit me?

  • SonicGenX

    Wow! Thanks for the tips! Now performance game on Bigfoot 4×4 Challenge and Counter Strike Condition Zero not bad! But, before I use USB to upgrade, it is choppy and slow. Now, I don’t worry about slow performance after fast the PC using USB. I am using 4GB USB to fast it. Thanks again to alternative work to fast it using USB! I think in future, can you please make a tutorial video?

  • Jento Pieters

    SD cards are possible as well.

  • AJ Funbox Curtis

    I bought a refurbeded acer aspire 5733, intell i5 , windows ready boost uped the preformance rating out of the box from 3.6 to 4.6 . its a great program good job guys

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