Windows Vista and a UMPC: ReadyBoost 101



After working long and hard to get Windows Vista RC2 nearly 100% functional on the Samsung Q1 UMPC, the next step is definitely performance tweaking. One of the first things I did in light of that was to read up on the ReadyBoost function in Windows Vista. If you haven’t heard of ReadyBoost, there’s a number of good sources that describe it in detail; some of them I’ll be referencing here for your after hours reading. Aside from an explanation, I’ll also share with you what I purchased specifically for using the ReadyBoost functionality on the Q1 UMPC. Remember, that Vista is running quite well on the 900 MHz Celeron based device; I previously upgraded the RAM to 1 GB, so let’s see what Ready Boost does for us!

So what is ReadyBoost and why do I care?

If you hit up the Microsoft Vista features page and look under performance, you’ll get the basics of ReadyBoost:

"Windows ReadyBoost lets users use a removable flash memory device, such as a USB thumb drive, to improve system performance without opening the box. Windows ReadyBoost can improve system performance because it can retrieve data kept on the flash memory more quickly than it can retrieve data kept on the hard disk, decreasing the time you need to wait for your PC to respond."

Think of it this way: it’s almost as if you’re adding more system memory to your device, which typically increases performance. The nice part is: you don’t have to crack open your computer to add the "boost"! If you’ve got a USB-based flash-drive with 256 MB of capacity or more, you might be able to take advantage of the ReadyBoost feature.

So, is it the same as adding more memory to my device?

Actually, no. You’re not truly adding system memory like you would with an updated memory module in your system board and the amount of RAM in your system properties doesn’t change. Essentially, ReadyBoost uses your flash storage as another disk cache. Of course the first question that comes to mind is: so if I add more drive space for cache, that’s the same thing right? Again, no not exactly. The different between additional cache space on disk and cache space on a flash drive is in the speed of access. You can typically retrieve data much faster from flash storage than you can from magnetic hard drive storage. On the other hand, large amounts of sequential data from a hard drive might be retrieved more efficiently than small, random bits of data; in the second instance, a flash drive excels.

Can I use any USB-based flash storage?

There’s a few requirements and guidelines around this and not all flash drives will work. First off, your flash drive must have a capacity of at least 256 MB and not more than 4 GB. Smaller than 256 MB and you simply wouldn’t gain enough benefit; 4 GB is the max due a file allocation size limit. Your flash drive also has to be quick enough for ReadyBoost. Don’t go by all of the package labeling on your flash drive, you’ll want to have storage that can transfer around 2 MBps. If you’re unsure that your device will work, don’t worry, Vista will tell you. In fact, if Vista says that your device isn’t fast enough, try this trick: shut down all unnecessary programs and processes, then have Vista try again. It could be that your flash drive is on the cusp, but other system resources took precedence. For a listing of devices that are known to work, check out the compatibility list that Grant Gibson maintains.

Where can I get more information on ReadyBoost?

My personal experience

Sandisk_sd_usb_1After reading up on Vista’s ReadyBoost feature, I decided to drop a few bucks for a SanDisk 1 GB Ultra II SD Plus USB card. At time of this writing, we had these in our Amazon store for $39.99 (Affiliate Link) and they really add flexibility with the dual format. They’re a typical SD card, but they fold in half and expose a USB 2.0 interface for devices without an SD slot or card reader. Since the Samsung Q1 doesn’t have an SD slot, this was a perfect accessory for me.

I took a chance on this card because I hadn’t seen anyone test it on Grant’s list yet. I figured in the worst case, I’d still have a dual-purpose card for the Q1 and for my other computers that do support the SD format. SanDisk claims write/read throughput of 9 MB/sec, 10 MB/sec, but you never know. Turns out, this card worked like a charm for ReadyBoost on the Q1 (and I need to let Grant know!).


Setup was simple in Vista. I simply popped the USB portion of the card into a USB slot on the Q1 and Vista immediately asked if I wanted to enable ReadyBoost. Vista also suggests an optimal cache size, so I went with the default. Essentially, Vista is using around 90% of my 1 GB memory card for a large cache, still leaving me with some external storage capacity.

Rb2 Rb3

I haven’t run any benchmark applications, but ReadyBoost has a noticeable performance increase in many areas. Applications open quicker, access to data appears faster and web-surfing is positively zippy when I’m hitting sites I’ve previously hit. Bear in mind that ReadyBoost really shines when fetching non-sequential data from the cache. You won’t gain any benefit when streaming audio or video, for example.

Here’s the interesting thing because I know someone will ask the question "What happens when you remove the flash drive?" It’s actually quite simple (and noticeable): system performance returns back to what it was prior to using ReadyBoost. There’s no device installs or uninstalls, the system just keeps on working minus the extra cache. When you need a "boost", you can simply pop your ReadyBoost device back in and BAM! You’re humming on all 8-cylinders again.

For mobile devices that would be marginal performers on Vista, ReadyBoost is just what the doctor ordered. The fact that you can use small accessories to gain the performance boost is perfect because there’s always room in the gadget bag for a high capacity flash drive, no?



nevermind….. i skipped a part of what you wrote, so thanx anyway.


hey, thanks for the tips, but here’s a stupid question. I was wondering if redy boost can boost up my RAM. I need about 15 RAM to play this game and im wondering if the redy boost can make that happen. If i don’t have to pay and put a chip in id be relly happy

Kevin C. Tofel

It’s just my opinion of course, but given the specs of your machine, I think the benefit of adding any more capacity to ReadyBoost would be marginal at best. In other words, if the benefit is a boost of 2% to 4% (just guessing), what’s that worth in terms of dollars? Is it worth $50 for a larger memory card? $100? I don’t know, of course and everyone would answer that question differently. I just wouldn’t expect much more of a ‘boost’ so I probably wouldn’t spend the money. Now, if I borrowed a higher capacity card from someone and saw a 15% or more boost, that would change the equation. Make sense? Hope that helps a little…


Thanks Kevin. Do you mean I wouldn’t benefit much from the 2:5:1 ratio as opposed to a 1:1, or a larger capacity card? It would seem that a 3GB card would be something I would get some benefit from?

Kevin C. Tofel

Unfortunately, there’s only one way to tell for sure and that’s to try a higher capacity SD card. Perhaps you can borrow one from someone?
Microsoft recommends “a 1:1 ratio of flash to system memory at the low end and as high as 2.5:1 flash to system memory. Higher than that and you won’t see much benefit.” With the specs that you quoted, I’m not sure you’d see much more benefit…


I have a new Sony Vaio SZ650 (dualcore 2.2). I upgraded to 3GB Ram, have the 160GB hybrid drive and have Readyboost set on a SanDisk Extreme III 1 GB Secure Digital (SD) Card 133 X Write Speed – 20 MBps Transfer Speed -SKU: SDSDX3-1024-901. The tech at Sony told me that I didn’t need more than the 1 GB of flash (he also told me I didn’t need more than the 3GB of RAM). I am running Vista Pro. It seems to be running fine, but would a larger compact flash drive do anything for me? Thanks


I agree linux has its place, its fast, flexible and secure. But the idea of a UMPC is to allow a user to do everything that they can on their main machine and take it with them.

With Windows being the main OS, it makes more sense for them to be windows, and then UMPCs can have real world tools like Office, OneNote and Visual Studio.

Linux on mobile devices is perfect for the N800s and Zaurus’ but you can’t beat being able to take the most widely accepted OS with you whereever you go.

And thats why having vista in your pocket is not for chumps.

Darksat SEO

or you could just use an OS that dosnt suck up all your resources.
Vista has this nifty little feature to speed up your PC cause Vista slows down your PC.
(forcing you to upgrade and buy new PCs preinstalled with vista)
No wonder microsoft is making a fortune.
Im using a windows XP/Backtrack Linux dual boot system on 512MB ram and it runs like lightning.
(custom shell so I dont have to load windows explorer elements)
an SD card for my pagefile.sys and Firefox/Opera for websurfing, A43 file explorer (800KB windows explorer replacement)
And my system runs like lightning (still strong after 2 years)
Vista is for Chumps
Now if someone knows where I could get readyboost for XP I would be interested in taking a look. (although I dont need it)
Anyway if you want a really fast PC, try installing Linux.


Since the CF slot is looked at as a hd, couldn’t you just put the page file on that drive and not on the HDD? Putting the swap file on the CF has to be faster than having it read and write to the HDD. Only drawback is that you cannot take out the card when windows is running. Any thoughts.


Anyone figure out a way to make the CF slot work as ready boost? The compact flash slot doesn’t stick out and the really fast & large CF cards are cheap. The problem right now is that the CF slot is considered a hard drive, so readyboost isn’t offered, even with the reg edits that have popped up to force Vista to use a slow card, it doesn’t work. =(


Friday, 11 March 2005
We are sorry to inform you that we have stopped the development and the support for our well established virtual disk product “AR RAM Disk”.


I have had vista running for about 3 months now, ever since RC1. Readyboost works amazing for me. I run a lot of virtual machines. And the harddrive on laptops are usually 5400rpm. My laptop is about 5months old. dell inspiron 6000. 2G of ram. running the virtual machines without ready boost halts the system to a crawl… i have a 4g SD card and a 4g usb stick. It seems the performance is a lot better with the SD card since the memory is rated at 150x… without this ready boost i would not be able to run 8 machines virtually on one laptop… thank god for this feature.


It seems like the ReadyDisk technology would work well for people with older computers and low funding for hardware upgrades. Flash ram is cheap, so all power to ReadyDisk. The only problem is I cannot afford neither the switch to Vista or more RAM. So now I really only need to know one thing:

When is somebody going to write a similar program for Win XP?

Andrew Herron

It’s not a placebo, yes the access speeds seem slow but that just means it needs careful management. Ask anyone who has actually tried it under low memory conditions, it works.

My PC has 1gb ram, and while playing games I often noticed lag and/or excess paging to swap. I picked up a cheap 2gb flash drive, dedicated 100% to readyboost and now I don’t need to buy extra ram. It makes THAT much difference!


“Essentially, Vista is using around 90% of my 1 GB memory card for a large cache, still leaving me with some external storage capacity.”……….that leaves you with 100MB tops for storage space and what are you going to store with 100MB?

My ultra cheap MP3 player 4GB of storage space and I find that to be insufficient~~

Vista’s ReadyBoost is just a PLACEBO effect on users out there………limited by USB transfer rates (Maximum 480Mbit/sec = 60Mbyte/sec; actual sustained value is about 25MB ~ 35MB at the most!!).

Its one of those BS technologies that may show benefits in benchmark scoring but have no real world effects on users!!

Dont get me wrong, Vista is great with all the graphics and all……but trust me, get 2 ~ 4GB of system memory is the best way to go for Vista~~

Keep USB flash drives for its original purpose and dont use it for what its not!!!!


I believe that ReadyBoost does more than just provide a RAM drive. I think it is intelligently placing the files on the USB drive that will make the biggest difference to performance. That’s just my opinion so if anyone (MS?) wants to chime in feel free.


John Christian, you have explained wonderfully what this is all about.

“A memory stick can improve performance in Vista simply because you extend the “available memory” if your system uses a page file a lot (hence you should really upgrade your system memory if you can).”

John Christian

Whatever is the point of making a ram drive to store a swap file? It kind of defeats the purpose doesnt it? If you have enough ram to free up for a RAM drive you could just as well turn off the page file all together or set your program to allocate more of the available ram (e.g. in Photoshop).

A ram drive is nice if there are certain programs you start a lot and you at startup copy them from the disk into the ram drive. But other than that it really has no purpose, as you are actually using precious system memory that the programs could have allocated instead.

A memory stick can improve performance in Vista simply because you extend the “available memory” if your system uses a page file a lot (hence you should really upgrade your system memory if you can). You also get the benefit as if you had 2 drives in your system, so the harddisk doesnt have to jump back and forth between a page file read/write and another programs file read/write. In laptops this benefit is more immediate because laptop drives are often pretty slow (4200 rpm) compared to a desktop.

All windows OS’es are built on NT swap file technology, and these are notrious page file users. It will even page out a minimized application almost immediately at times. So if you are having problems with this, go out and buy another gigabyte of system memory and turn off your page file.

Lorie Ghamy

Hello Kevin and others,

What could be the power gain with Windoxs XP Tablet PC and just the free AR Soft RAM Disk Driver.

“The AR RAM Disk is a freeware driver for Windows NT or Windows 2000 (and XP). You can use this driver to create a additional drive in your memory. This drive can be used for storing temporary files, this can increase your system speed”…

You can use it too with virtual memory settings in Windows XP for a swap file.

So Kevin,AR Soft RAM Disk Driver VS ReadyBoost with you 1 Go of main RAM (or combined with the secondary RAM) what is the best way ?


I found one case where ReadyBoost works where RAM caching fails – startup. The OS can access data in non-volatile flash to speed up boot times before the disk has had a chance to cache data in RAM.

Also, I still would like to see some more benchmarks showing any benefit to ReadyBoost.


“I still dont see why you cant allocate some sort of ram disk from main memory.”

RAM is a fast place to get data but eventually, in the current PC architecture, the OS will have to go to the disk for data. Why not just load that data into RAM? I’m sure that’s what SuperFetch does, but I’m not sure the trade-offs.

Tax Man

50, KCT , are you going to post a how-to on getting Vista to work 100% with the Q1 at some point? Can I still get RC2from some place online or is the Beta totally over?


Is there a utility/program for this in XP also? I have a Sony U50 which only has 256 MB of RAM, but features both a CF and MemoryStick slot…


Is this getting us ready to use hybrid drives? Or is the functionality for that technology going to be more transparent?

Steve Paine

Great article!

I still dont see why you cant allocate some sort of ram disk from main memory. OK it might require 3rd party software, but my 7210 usually has a good 300MB that I coud allocate to cache. Mind you, the SD reader on this device is so fast (6MBps with no-brand cards the I have) that it’s probably easier to go to the ready boost route.

Thanks again for the article. I’ll link to this tommorrow.



Would this work with a CF card (using the built in CF slot)? Or is that not treated as a drive?


…. and having system reading flash drive insted of spinning normal hd should give us more battery life.

Can you notice any difference on that Kevin?

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