[achtung]

External memory devices
Adding system memory (RAM) is often the best way to improve your PC's performance. More memory means more applications are ready to run without accessing the hard drive. However, upgrading memory is not always easy. You must learn what type of memory you need, purchase the memory, and open your computer to install the memory—which sometimes can invalidate your support agreement. Also, some machines have limited memory expansion capabilities, preventing you from adding RAM even if you are willing to do so.
Windows Vista introduces a new concept in adding memory to a system. USB flash drives can be used as External Memory Devices (EMDs) to extend system memory and improve performance without opening the box. Your computer is able to access memory from an EMD device much more quickly than it can access data on the hard drive, boosting system performance. When combined with SuperFetch technology, this can help drive impressive improvement in system responsiveness.
EMD technology is both reliable and secure. You can remove an EMD at any time without any loss of data or negative impact to the system; however, if you remove the EMD, your performance returns to the level you experienced without the device. Wear on the USB drive is not an issue when using it as an EMD. A unique algorithm optimizes wear patterns, so that a USB device can run as an EMD for many years, even when heavily used. Finally, data on the EMD is encrypted to help prevent inappropriate access to data when the device is removed

Taken from the Windows Vista site.
http://www.microsoft.com/windowsvista/

Sounds like an interesting feature to me.  Could easily be screwed up though.

[CP5670]

huh? I thought flash drives have way higher seek times than hard disks.

[karajorma]

And lets ignore the MS crap about removing the drive at any time. You're going to have to wait for it to swap the information to your memory or VM.

[aldo_14]

FATAL SYSTEM ERROR

MEMORY ACCESS ERROR AT ADDRESS EXT22-0454-05F-05B-0FA

You may have removed an external memory accessory device without initialising the external memory desyhnchronizer console (start->menu->vista->main->system->system properties->devices->external->memory->non-microsoft branded products->type->desynchronisation methods->desyncher->unplug.exe)!  Due to virtual memory delogification, you may experience an increased amount of seemingly random crashes and strange bleepy noises.  To rectify this problem, please contact your nearest Windows reseller and arrange for a service person to visit and either reinstall windows or hit your monitor with a hammer for 3 hours.

Please select a recovery option;
ABORT?  CORRECT? RETRY? SHUTDOWN?



>> A
*Abort failed*
>> C
*Unable to correct*
>>R
*Retry attempted*
*Retry failed*
*ABORT?  CORRECT? RETRY? SHUTDOWN?*
>>S
* Unable to shutdown*
* Please purchase service pack 3 to correct this error*

[Sandwich]

Sounds like a load of BS to me.

[castor]

Could be useful, yes. In the way the marketing hype is telling us? Hardly.

[Martinus]

External memory devices have a limited number of read/write cycles. After which they fail. Your bog-standard USB keydrive was never designed to be used in such a fashion.

[Descenterace]

huh? I thought flash drives have way higher seek times than hard disks.

They have lower bandwidth, certainly. I think seek times are faster.

USB2 allows for 40MB/sec transfer rate. ATA and SATA hard disks are currently limited to about 100MB/sec effective transfer rate, although the busses can cope with up to 133MB/sec and 300MB/sec respectively.
For comparison, most computers' RAM transfers data at about 2GB/sec effective transfer rate, peaking at 3.2GB/sec under certain conditions.

So yeah, Microsoft's marketing department is once again promising the world the impossible without consulting the poor bastards who will have to implement it.

[vyper]

FireWire to the rescue!

[phreak]

Sounds like a good idea, but the transfer speeds of USB compared to main memory will trash this.

[Descenterace]

FireWire to the rescue!

Not really. Firewire 800 is the only version faster than USB2, at about 80MB/sec under ideal conditions.

[Stealth]

And lets ignore the MS crap about removing the drive at any time. You're going to have to wait for it to swap the information to your memory or VM.

but how does hot-swap RAM work then?

[karajorma]

but how does hot-swap RAM work then?

No idea. RAID-like I'd guess, with multiple banks and parity used so that the information on any one bank can instantly be recreated should it be removed.

Either that or it does back up to one of the other chips before you remove one. Never used the stuff but it must be something like that cause you can't simply remove a memory chip and expect your PC to keep functioning as you've just corrupted your RAM.

[Descenterace]

Probably a RAID-like system, yes. Either that or the boards have a two-stage removal process which leaves time for the data to be dumped between stages.

[SadisticSid]

When I first heard about this I thought it involved caching pre-initialised application code on these USB devices to accelerate their startup, which might've made sense. But if this is simply spreading the page file over a number of devices dynamically (not an immense feat of programming) then it's worthless.

BTW it's not possible to have hot-swappable 'RAM' and then call it a memory extension. Redundancy, yes, but to be able to replace lost data you have to store additional data necessary to reconstruct it somewhere, or have an extra copy. I expect Vista will store non-kernel memory pages on these EMDs so as not to crash the system should they be removed - applications may not gracefully exit or be blocked until until the device is replaced. I can't see the point either way.

[ZylonBane]

This sounds like an amazingly stupid idea thought up by the marketing department. Even if it could be made to work (which seems bloody impossible... hot-swappable RAM??), the access speed would be glacial compared to main RAM, and the idea of having a memory upgrade permanently occupying one of the USB ports just seems absurd.

[DeepSpace9er]

Wouldnt it be cheaper to compile a PDF explaining how to install ram depending on which computer u have by major brands? If you dont know how to add ram, take it to a shop to do for u or learn.

This idea MS has doesnt seem very practical. I dont know many people who like to take their RAM in and out of their comp on a day by day basis.

[vyper]

I can see where the thought comes from: people can install their own "memory upgrades" without needing to go to a shop. Sadly though, has has been explained above, it's not possible in any practical way.

[Bobboau]

it's not so much takeing it to a shop, it's the thought of oppening up there computer and doing it, for many people the idea of allowing a screwdriver within a fifty foot radius of there computer is a terifying one.

[Descenterace]

So they pay people like me to do it for them.

I don't see a problem here.