At first i thought ReadyBoost means having swap file allocated to flash drive which is wrong because ReadyBoost serves as additional storage for swap file or should i say it mirrors swap file on hard drive and has first priority?

Anyway, i thought about allocating swap file to flash drive fully. How would that perform? Will it deplete flash drive's write cycles fast? I also think it would be more convenient with SD flash card since it sits inside laptop's flash reader and does not stick out.

Now the best option is to buy more RAM, but what if to create RAM disk out of current 4GB of RAM that i have and fully allocate swap file there? Create 2GB RAM drive or just buy additional 4GB of RAM and create 4GB RAM disk?

My objective is to have swap file on flash media or better on RAM disk. While latter sounds better, it would be more expensive and will require disassembling my DELL Latitude E6420 laptop (i did not find RAM cover).


Ram drive idea is dead on arrival.

If you make 2GB ramdrive you are left with 2GB for system memory. So you swap a lot more. But you have overhead, so you will be worse off than now. Buying 4 more and just disabling swap is better solution.

Having swap on flashdrive can work if you have usb 2.0 and very high quality flash drive, but it will burn quickly because you lack the ssd controler that gives tear leveling.

So - third best solution - buy SSD.

Second best - buy more ram.

Best option - buy both :)

  • As Foo_Chow noted, moving a swap to a flashcard is also DOA. If the flashcard loses connection, then that's a bluescreen. – surfasb Aug 17 '11 at 20:01
  • Where you heard that? – Boris_yo Aug 17 '11 at 21:17
  • Who needs controllers? This USB drive already has it: i.imgur.com/uIGVF.png – Boris_yo Aug 17 '11 at 21:29
  • Connection != controller. Unplugging your pagefile is similar to unplugging a memory module. Unplug a memory module and you'll bluescreen. – surfasb Aug 18 '11 at 5:57
  • Upvoted for everything except the third paragraph. Windows will not let you create a pagefile on a USB drive. So, no, it can't work. – Jamie Hanrahan Jan 25 '16 at 12:03

Moving the swap file to an external source entirely, or on to a RAM disk entirely is a bad idea. Of course you can do whatever you want.

The mirroring you suggested is more accurate of a statement. As it is unknown when the USB or alternative media will be unplugged, the swap area has to be protected from such events. The flash wear would be negligible, you will most likely change to a different solution before that kicks in. The issue with the RAM disk is that when the laptop is powered off (even unintentionally) the swap file will disappear with the RAM disk.

  • Great, if laptop is powered off i don't need swap anyway. As soon as OS loads, new swap file is created. – Boris_yo Aug 17 '11 at 21:19

At first i thought ReadyBoost means having swap file allocated to flash drive which is wrong because ReadyBoost serves as additional storage for swap file or should i say it mirrors swap file on hard drive and has first priority?

Sorry, but none of the above is true.

What ReadyBoost ("use removable device to improve Windows performance", or whatever the exact wording is) does is to allow SuperFetch, which is the proactive disk caching feature that first showed up in Vista, to use some of the USB device as an addition to - not a mirror of - RAM.

You could view this as a "mirror" of the cached files' contents. Not of RAM, nor of the pagefile. The pagefile will not ever be cached by SuperFetch.

The result is to allow SuperFetch to work well even on systems with limited RAM.

If you're in a situation with not enough RAM (your hard pagefault rate is high), then this will help SuperFetch work better, but that will be its only benefit. Except for a small amount of key system files, SuperFetch's use of RAM is low priority so Windows will not give RAM to SuperFetch when it's needed for other things. The USB storage, on the other hand, can't be used as a replacement for pagefile or RAM space in any other way, so SuperFetch is allowed to use it.

Is SuperFetch important to you? Maybe. It depends mostly on what your file access patterns are like. SuperFetch pre-reads frequently- or recently-used files into available RAM (or, if you enabled ReadyBoost, a USB drive), in case you need them again soon. It even tries to be clever about noticing when you use certain files. Like if it notices that you open your email client at about 8:30 AM every day it will start pre-loading your email files (.PST or .OST or whatever) a few minutes before that.

As for a pagefile - Windows will simply not let you create a pagefile on a USB drive, unless you have some hack in place (or a bug in your USB drive, or in your USB host controller) that fools Windows into thinking the USB drive is non-removeable. You can argue that it ought to let you do that ("I promise, I won't remove it!"), but fact is, it won't. It won't even offer a USB drive in the virtual memory configuration dialog. If you hack it into the registry, it will ignore that setting.

The reason is that, as @foochow mentioned, the pagefile contents are critical to Windows' continued operation. If you did manage to get a pagefile on a removable drive, and it was removed while the OS was running, the OS would crash the moment it tried to read or write to the pagefile.

This concern does not apply to SuperFetch, because there's nothing in the SuperFetch cache that isn't still accessible in the files that SuperFetch is cacheing. If you yank a USB drive that SuperFetch is using, and you later need something from the cached files, it'll just be read from the files.

(This by the way is why we say that SuperFetch doesn't really "use" RAM: The RAM occupied by SuperFetch'd file contents can be immediately released for other, higher-priority uses, just as if SuperFetch had never used it at all. The only bad result is slower access to the formerly-cached content. Therefore the RAM "used" by SuperFetch is still considered part of "Available" RAM on e.g. Task Manager's display.)


As others said, having a swap file on a RAMdisk makes no sense whatsoever, because the whole point of a swap file is to extend RAM. If you add a RAM disk you are taking away from RAM the size of the RAMDISK, and you add back the same amount of with the swapfile in the RAMDisk so the end sum is zero gain. In fact you are worse off because of the overhead of a RAM disk.

So forget the RAMDisk for this, that is for completely different things.

Given your other options, by far, the fastest solution is if you buy more RAM, since RAM is much faster than even the fastest SSD. If you add 4 more Gb for a total of 8 you should be able to disable the swap file completely unless you're a really heavy user. Or leave a minimal swap file which will not be used that much because you already have 8Gb Ram.

Your second best option is an SSD. In fact now they have really micro format SSD-s called M.2, however if you get one of these and keep the 4gb of RAM it will not speed up your performance as much as option one, since with 4gb of RAM the swap file will still be used a lot, and even the fastest SSD is way slower than RAM.

As for USB and flashdrives, as others said those are not designed for this purpose and would be the slowest alternatives, even if you can hack it it might not even be any performance benefit over your base setup. This would depend on a lot of things such as is it USB 2 or 3 and how fast the flash drive is itself. It might be possible with a special drive like the SanDisk Extreme, but not with ordinary ones.

But before all this, one question: is your primary drive an SSD? Because if you're still running off a traditional HD and thinking about all this, getting an SSD for your primary drive will be the best investment of all.

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