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http://www.bargainpda.com/default.asp?newsID=2670
The X51v is overflowing with memory. Dell has doubled the amount of internal flash memory to 256 MB. Between this, and the new memory system used by Windows Mobile 5, you'll almost never have to worry about running out of memory again.
Before delving into the technical details, it's handy to know a couple of basic points. "Storage memory" acts like a desktop's hard drive, the area where you keep files and programs. "Program memory" is like a desktop's RAM, and is used by active programs.
The newly upgraded 256 MB of flash memory in the X51v forms the biggest change from the Axim X50v. Under WM5, this area houses both the operating system, and the device's primary storage. Minus room for the OS, you're left with a whopping 195 MB of storage memory on the X51v.
Both of the two lower models in the X51 series have 128 MB flash memory. This is the same as the X50 series for the mid-range device, but double what the low-end received last time around, a very fair upgrade.
Prior to Windows Mobile 5, the primary storage area of a PocketPC was a chunk of the device's RAM. Applications could be installed on memory cards or elsewhere, but the RAM served as the home of Windows files and other essentials. Since RAM required power all the time in order to maintain its contents, increasing available memory also meant significantly increasing the battery drain. Now all those files and programs have been moved into flash, storage memory can be increased without a battery life penalty. The X51v has 256 MB internal flash, but it wouldn't be impossible to build a device with 512 MB, 1 GB, or even more.
Besides pure speed, flash memory does have one significant drawback over RAM. After a certain number of rewrites, flash memory begins to degrade and show errors. Fortunately, the number of rewrites is quite high, anywhere from 100,000 to 1 million writes per sector. So while the flash in the X51v will eventually deteriorate with continual use, it's not likely to happen before the march of technology turns it into a doorstop anyway.
Thanks to the new memory arrangement, storage memory isn't the only thing that gets a boost. On prior Windows OSes, the system's RAM was divided more or less evenly between storage memory and program memory. Hence, a Pocket PC that had 64 MB of actual RAM effectively used only 32 MB of it for program memory. To get a full 64 MB for running programs, you needed to buy a 128 MB PocketPC.
Under WM5, all of a device's RAM, in this case the full 64 MB, is used for running programs. This makes a 64 MB WM5 device the equivalent in program memory of a 128 MB WM2003SE or earlier model.
If all this talk of storage, program memory, and etcetera has you confused, don't worry. The new system used by WM5 is actually much simpler than its predecessor. The X51v's main storage, where all of its files and programs are kept, is flash memory. This works more or less like a desktop hard drive, and retains its contents even if your battery dies. The RAM, like the RAM on a desktop, is used only for running active programs, and doesn't get maintained if your battery dies.
The new handling of RAM does mean that a fully drained battery can still result in some data loss for open documents and programs, because the RAM isn't backed up against loss. It's equivalent to having your PC reboot--everything returns to the way it was the last time you started it up. Likewise, any time you change your battery, no matter how fast you do it, you'll end up with a soft-reset. I'm not particularly happy about this, since it's very annoying when you have to wait for your handheld to reboot following a quick battery swap, but that's the way it is.
