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Dell Axim X51v

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Review posted Sept. 20, 2005 by Lisa Gade, Editor in Chief

Once again, Dell is first to market with a Pocket PC running the latest version of Windows Mobile 5.0. Just as their Axim X30 was the first Windows Mobile 2003 Second Edition device to hit the US market, the X51 and X51v are the first WM 5 PDAs. And just as the X30 looked identical to the Axim X3 it replaced, the X51v is identical in appearance to the X50v it replaces. In fact, the resemblance is more than skin deep, the X51's hardware is identical to the X50's, and the X51v's is identical to the X50v, with two exceptions. The X51v has double the flash memory and the X51 models are now lead-free to comply with upcoming European regulations.

Dell Axim X51v
Dell Axim X51v back


The X51v is every bit as solid, reasonably priced and full-featured as the X50v it replaces. It's certainly an excellent contender if you're in the market for a new PDA. If you're an X50v owner, you'll likely skip this model and opt for Dell's Windows Mobile 5.0 upgrade CD which will be available September 30th (though you'll lust for that 256 megs of flash memory!). If you do own an X50 or X50v and upgrade to the new X51, you'll be able to use all of your existing accessories including cases, keyboards, screen protectors and GPS. Some of you may be disappointed that the X51v doesn't offer significant hardware upgrades, but to be fair, the X50v was already very well appointed, and Dell told us that getting WM 5 ready and working for consumers took a great deal of engineering effort. Creating a new hardware platform would have further delayed release of a Windows Mobile 5.0 Pocket PC.

Windows Mobile 5.0

Microsoft's latest operating system, Windows Mobile 5.0, offers many improvements; the most important being persistent memory. All data and applications are stored in flash memory which will survive a complete battery rundown. No need to leave it on the charger when you go away for a 2 week vacation. Just charge it up upon return and your data will still be there! WM 5 devices still have RAM, which is volatile and faster than flash ROM. But RAM is now used in the same way your PC uses it: running programs are loaded into RAM and operating system files are cached there to improve response times. You can no longer install programs or files into RAM, only flash ROM. Since the device need not power RAM at all times, battery life is improved by approximately 10%.

Windows Mobile 5's improved user interface makes some tasks a bit quicker and more intuitive and Internet Explorer, Word Mobile and Excel Mobile are more capable. In addition, you get a Mobile version of PowerPoint which can open and run but not create or edit PowerPoint presentations. To learn about Windows Mobile 5's new features in detail, read our article here.

Design and Ergonomics

Here's where our review will parrot our X50v review, since the X51v's physical design remains unchanged. Though Windows Mobile 5 provides two softkeys at the bottom of every screen which are shortcuts to frequently used applications or commands, Dell did not add hardware buttons for these. Instead, you'll tap the softkey location on screen to activate that function.

The Dell has curves and good looks. Like ASUS, Dell went with the curvy bottom design found on older, more attractive HP iPAQ Pocket PCs. Despite the large VGA display and CF slot, the X51v is certainly not a very large Pocket PC and is mid-sized. It feels great in the hand thanks to the bottom and back curves and weighs in at 6.2 ounces.

side of X51v







The X51v has a plastic casing. The back is matte black and curves to cover the sides of the PDA. The front has a silver surround that wraps around the gloss black plastic upper and lower front faces. It looks sleek, contemporary and was designed by HTC. Those of you familiar with the Dell Axim X3 and X30 will immediately recognize the 5-way directional pad, though it takes a smaller form on the X51v. In fact, the d-pad is as small as you can go without forgoing usability.

The four front application buttons are round and relatively small, but are still very usable. From left to right they launch Calendar, Contacts, Email and Dell's Home launcher. As with all PDAs, you can assign different applications to these buttons.

The power button is located top center, while the voice recorder and wireless radio on/off buttons are located on the left side. Above these two buttons on the left side you'll find the hold slider switch which will prevent all buttons (even the power button) from turning the unit on accidentally. Since the side buttons are easily accidentally pressed, that's a good thing. The SD and CF slots are on the top edge, as is the IR window and the standard 3.5mm stereo headphone jack. The user replaceable battery lives under a door on the back and there's a battery lock switch to keep the battery in place. The metal and plastic stylus lives in a silo on the top right corner. The stylus end is small so you'll want to have a good fingernail to get it out.

size comparison

Size comparison: HP iPAQ hx4700 VGA Pocket PC and the Dell


The mic is located on the top left corner and the speaker is under the d-pad, so if you want to use this with VoIP apps, you'll likely need to hold it upside down or get a stereo headset with mic. The unit has a single LED on the top right corner which flashes blue when one or more wireless radios are on. As with other Axim models, the power button lights amber when the unit is charging and glows green when fully charged. The power button flashes amber when a reminder goes off.

Horsepower and Expansion

The X51v is in the top tier of current Pocket PCs thanks to its 624MHz "Bulverde" Intel XScale PXA270 processor. Currently, only the high end Dell Axim X30 model (QVGA) and HP iPAQ hx4700 run the same 624MHz processor. As you'd expect, the unit is fast, though you may see the slightest delay opening menus and windows since the device is running at VGA resolution and uses ROM rather than RAM for application and file storage. It is up to the task of even the most demanding applications including action games and video playback. WM5 is a bit slower than Windows Mobile 2003 because applications and data reside in ROM which is slower than RAM. We noticed a half second additional delay dropping down the Start Menu and launching programs takes a second longer, despite the operating system's caching of files in RAM which is faster than ROM.

Windows Mobile 5.0 caches operating system files heavily to improve performance, and uses a significant portion of available RAM. At boot, 49.47 megs of RAM are shown as available, and another 19 megs of that available memory are used by the OS. That means you'll have about 30 megs out of 64 available to run programs. That's certainly adequate even for power users, but it's surprising how much of that 64 megs is used by the device.

The unit has 256 megs of flash ROM, 195 of which are available as internal storage. The operating system and related programs are permanently installed in the remaining 59 megs of ROM. Dell always uses Intel StrataFlash memory for flash ROM which is faster than NAND. Though all data is stored on non-volatile ROM, you can still hard reset the device if needed to clear out all of your personal data. No special utilities are required, simply press the soft reset hole and power button simultaneously to bring up the hard reset option, just as with the X50v.

For expansion, the Dell offers standard (not consumer) IR, Bluetooth, a CF slot compatible with type I and type II cards and an SD slot supporting SDIO and SDIO Now! All these expansion options make for a very versatile and expandable device that will work with CF cellular cards, GPS, presentation, modem and networking cards.


We use Spb Benchmark to test PDAs. Since the Axim offers a variety of CPU speed settings in the battery control panel applet, we benchmarked it in Auto mode, where the PDA sets processor speed relative to current program demands. As with prior Axim models, we were impressed with Auto mode's ability to step up processor speed whenever improved performance was needed and found that Auto and Max benchmarked similarly.

The X51v does well on CPU intensive benchmarks thanks to its 624MHz processor. Like the X50v, it uses Intel's G2700G graphics processor with 16 megs of RAM. While the 2700G is a 3D accelerator it does offer some 2D acceleration which should help it in 2D graphics benchmarks and in general responsiveness when using non-3D applications (games make use of 3D while most other apps would not). That said, many Windows Mobile applications, including Spb Benchmark don't take advantage of the Open GL capabilities of the 2700G and test GAPI, which isn't that graphics accelerator's strong point. The folks at Futuremark, well known for their PC benchmarking application, have released a Pocket PC benchmarking app called SPMark 04 which tests 3D graphics on WM2003SE and WM5 Pocket PCs. The X51v managed an average 24 fps on the low detail scene and 9 fps on the high detail scene.

Windows Mobile 5.0 devices score much lower on file system and application launch tests since they use ROM rather than the faster RAM for storage. This greatly reduced File System Index in turn brings down the overall Benchmark Index, since the file system tests account for 25% of that total score. Certainly, it's worth the tradeoff, since your data is safe from battery drain related hard resets, and the device doesn't feel seriously slower than WM2003SE devices on file access and launch. But if you're one of those folks who craves the device that tests best on benchmarks, in general, WM5 devices won't give you that high. Spb's test is a pure test, as they put it, and thus VGA devices test slower than QVGA and the new Windows Mobile 5 persistent storage isn't taken into account. In their next revision, they will offer relative benchmarks that compensate for these differences. For example, they say that a VGA device's scores could be multiplied by 4 to reflect that they are drawing 4x more data to the screen than a QVGA device.

  Dell Axim X51v Auto mode
Dell Axim X50v Auto mode (WM 2003 SE)
HP iPAQ hx4700 624MHz VGA (WM 2003 SE)
Spb Benchmark index
CPU index
File system index
Graphics index
Platform index
Write 1 MB file (KB/sec)
Read 1 MB file (MB/sec)
Copy 1 MB file (KB/sec)
Write 10 KB x 100 files (KB/sec)
Read 10 KB x 100 files (MB/sec)
Copy 10 KB x 100 files (KB/sec)
Directory list of 2000 files (thousands of files/sec)
Internal database read (records/sec)
Graphics test: DDB BitBlt (frames/sec)
Graphics test: DIB BitBlt (frames/sec)
Graphics test: GAPI BitBlt (frames/sec)
Pocket Word document open (KB/sec)
Pocket Internet Explorer HTML load (KB/sec)
Pocket Internet Explorer JPEG load (KB/sec)
File Explorer large folder list (files/sec)
Compress 1 MB file using ZIP (KB/sec)
Decompress 1024x768 JPEG file (KB/sec)
Arkaball frames per second (frames/sec)
CPU test: Whetstones MFLOPS (Mop/sec)
CPU test: Whetstones MOPS (Mop/sec)
CPU test: Whetstones MWIPS (Mop/sec)
Memory test: copy 1 MB using memcpy (MB/sec)

Video Playback and Gaming

Video playback is excellent on this unit. Watching videos stretched to full screen is a lovely thing and will sell you on VGA Pocket PCs. We tested the unit with the included Windows Media Player 10 Mobile and TCPMP, an excellent free 3rd party video application. The X51v has a codec for the 2700G graphics processor to optimize video performance in WM10, and it shows because playback, even in full screen is impressive.

TCPMP played back "The Chosen" (a BMW short film that's 4:26 minute long, 10 meg MPEG1 file recorded at 320 x 240, 308 kb/s) with impressive benchmarks of:
Average speed: 779.77%
Bench Frame Rate: 187.14
Bench. Data Rate: 2.4 Mbit/s
Orig. Frame Rate: 24fps
Orig. Data Rate: 310 kbit/s

That's a bit better than the X50v, and likely both Dell and TCPMP have tweaked code since that device's release, resulting in better numbers for the X51v.

Despite the big changes in WM5, we're happy to report that most games ran just fine. We tested Jamdat's Tennis Addict, Arvale, Bejeweled 2, and Ancient Evil which all ran fine. Mobilair's Creepy Pinball did not run (frozen with a blank screen). Street Duel got a gwes.dll error on launch but still ran.

WiFi and Bluetooth

The X51v has integrated WiFi 802.11b wireless networking and Bluetooth 1.2. To turn on the wireless radios, simply press the button on the left side of the PDA. As with the Dell Axim X50v, this button will turn on both wireless radios, which seems a little odd, but you can turn them off using the on-screen management utilities. WiFi has excellent range and was reliable for us connecting to 802.11b access points using WEP encryption. The X51v comes with Funk Odyssey VPN client and supports 64/128 bit WEP, WPA and CCX 1.0. Dell includes their excellent WLAN application for managing WiFi connections, and this full-featured utility that lists available networks in range (shows SSID, channel, signal strength and mode), shows data transfer stats, lets you set the default network and power saving mode and more.

Unlike the X50 line, the X51v uses Microsoft's Bluetooth stack rather than Broadcom's excellent Bluetooth drivers and software. Microsoft's Bluetooth software lacks Broadcom's user friendly wizard, but still gets the job done. The device supports standard profiles such as ActiveSync, DUN, serial port and HID (keyboards and mice). We tested the Think Outside Stowaway Universal Bluetooth Keyboard using just the built-in Bluetooth profile and associated system drivers and it worked perfectly (minus support for programmable Fn and hotkeys, which require keyboard-specific drivers). Surprisingly, the Dell Axim X51v seems to lack fully functional hands free and headset profiles, though the standard Microsoft Bluetooth stack supports these profiles. We tried pairing to Bluetooth headsets such as the Motorola HS820 and were able to, but the Axim wouldn't use the headset (the set as hands free option was grayed out).

Display and Multimedia

As mentioned, the X51v uses the Intel 2700G graphics processor with 16 megs of RAM. That's an impressive amount of video memory for a PDA, and beats out all other models on the market. The 2700G comes in two versions with 384k and 704k of on-die video memory, but the chip can address additional external memory and that's how Dell got 16 megs into this model. The graphics processor also offers 3D acceleration, while all other PDAs except the now discontinued gaming-oriented Palm OS Tapwave Zodiac have only 2D acceleration if any at all. The 2700G was designed by Intel to work with the PXA270 family of processors, and it has a fast pipeline between the CPU and graphics processor. The graphics accelerator really shines for GDI and Open GL based software rather than GAPI which is currently most commonly used by Pocket PC applications, especially games. Since the benchmarks thus weight GAPI tests more heavily than GDI tests, the X51v with its 2700G processor doesn't get overall high scores in benchmarks. For those of you who aren't mega-graphics chip geeks, GAPI stands for game API (application programming interface), GDI stands for graphics device interface and Open GL is a common standard for 3D used on many desktop games. GAPI and GDI provide software developers with two ways of sending data to a graphics device, with GAPI being the commonly used standard put forth by Microsoft for Pocket PCs. GAPI allows a program to write directly to graphics memory and is in some ways the Pocket PC version of MS Direct Draw for PCs. It did however do very well on Futuremark's 3D test with a score of 24 fps on low detail and 9 fps on high.

The X51v ships with three Open GL games that show off the unit's 3D performance: Fathammer's Toy Golf, Ion-Fx' GeoRally and the 3D puzzle game Enigmo which look gorgeous and run well on the Axim. Dell promises some more top game titles for the X51v by Christmas 2005, and we can't wait!

The 3.7" LCD is sharp and bright. Text is clear even at the smallest type settings. While not stunningly vivid like the iPAQ hx4700, the screen is still very good and will please those who want to view photos or videos. The 2700G supports video mirroring, and both the older X50v and the X51v have a Mirror Mode control panel that allows you to enable mirroring when using a presentation card to connect the Dell to an external display. This is a feature you won't find on other Pocket PCs. Like the X50v, if you chose to calibrate the display, it may have you run through the calibration points several times rather than a single pass.

The Dell has a VGA 640 x 480 resolution display, while standard QVGA Pocket PCs have QVGA (quarter VGA) 240 x 320 resolution displays. That means you'll see more on screen, but not four times more, even though VGA is four times higher resolution than QVGA. Why? Microsoft's implementation of VGA is designed to make the display very attractive and readable rather than cram true VGA into a small screen. That means those with good or poor eyes can use a VGA Pocket PC, but if you were hoping to see four times more on your screen, you'll be disappointed. Nothing has changed with Windows Mobile 5.0 in this respect— sorry folks.


Though the Axim X51v is reasonably priced for the hardware you get, Dell has included a nice software bundle. You get Funk Odyssey VPN client, WLAN (a full-featured WiFi manager), Resco Picture Viewer (an excellent photo viewer), Battery Pack Lite, Data Backup which backs up your PDA to a storage card and the cool VGA 3D games Enigmo by Aspyr, GeoRally and Fathammer's Toy Golf (think miniature golf in a Toy Story setting). All three games look fantastic on the Dell and really show off its VGA and 3D capabilities.

Of course, you get the Windows Mobile 5.0 operating system and standard application suite which includes Mobile versions of MS Word, Excel, PowerPoint, Internet Explorer, Windows Media Player and Outlook. Windows Mobile 5.0 devices sync only to the new 4.0 version of ActiveSync, which is included on the CD. Note that you can sync over USB and Bluetooth, but not WiFi using ActiveSync 4.0. Microsoft felt that WiFi networks are inherently insecure, so they dropped WiFi syncing for now. You can however use a VPN connection over WiFi to sync. Like all Windows Mobile devices, the Axim syncs only to Windows desktops and Outlook (Outlook 2002 for the desktop is included). There are 3rd party syncing solutions for Mac users, which will require updates to support WM5.


Though a lot has changed in WM5, we found that most of our favorite 3rd party applications ran on the Dell. Many developers have already updated their applications for compatibility as necessary, so if you're running popular and regularly updated software things look good. We tested Spb PocketPlus 3.0 and Battery Pack Pro 2, both of which are WM5 compatible and they ran fine. Resco Explorer 2003 and 2005 as well as Resco Photo Viewer run well, as does TCMP (The Core Media Player, formerly Beta Player), MS Reader and eReader. Conduits Pocket Artist 2.7 worked, though one menu is mostly hidden under the newly centered keyboard input icon, so you need to tap near the edge of the keyboard to bring up that menu. The only problem we found is that the device sometimes won't wake up when the power button is pressed, required a soft reset (reboot) to get it up and running. Likely Dell will fix this quickly with a ROM update.


The X51v has a 1100 mAh Lithium Ion battery that's user replaceable. We'd hoped Dell would have upgraded the battery from the X50v, but no such luck. WM5 does offer approximately 10% better battery life than older versions, so the X51v will run a bit longer on a charge than the X50v it replaces. That's an average capacity battery for a Pocket PC, and low for a 3.7" display VGA model running at 624MHz with dual wireless (large displays, wireless networking and fast processors consume lots of power). That said, battery life is average for a Pocket PC, giving about 3 hours and 15 minutes of actual use in average conditions consisting of PIM use, working with MS Office documents, surfing the web for an hour using WiFi, gaming for 45 minutes and playing a few short videos. If you need more power, Dell sells an optional 2200 mAh battery which will increase the thickness of the PDA. If you're a heavy wireless user, you may want to consider this extended battery or a second standard battery. In our video test, the X51v used 43% of its charge playing a 1 hour 20 minute film using Windows Media Player 10. Brightness was set at 66%, WM10 was set to stretch video to full screen and we had sound piped out through stereo earbud headphones.

Let's face it, we don't need 624MHz all the time, but we may need longer runtimes when on the road. That's why Dell allows you to set the CPU speed to Power-Saving (208MHz), Normal (520MHz), Maximum Performance (624MHz) or Auto which sets processor speed relative to demand. Auto can set the CPU from 104MHz up to 624MHz depending on load and gives great performance overall. I found the Power-Saving mode to be too slow even for PIM lookups and working with Pocket Word documents, but Normal mode is just fine and may get you 15 minutes more out of your battery compared to Max mode.

Like prior Dells, you can charge the unit in its cradle or use the included dongle adapter to plug the charger directly into the PDA. This world charger is the same model included with the X5, X3 and X30, but the connector and thus dongle adapter are different. This means you can use chargers from your old Dell with the X51v as long as you use the X51v's adapter, but you will not be able to use cradles meant for other Dell models. And of course you can use all Dell Axim X50 chargers, adapters and accessories with the X51.

If you press and hold the power button, you can assign one of three possible functions using the Power settings applet. These are: dim/turn on backlight (that's the standard for older devices), turn the unit completely off (running programs will be purged from RAM, same as when you shut down your PC, and the device wil consume no battery power, nor will alarms and reminders fire), or Unassigned (do nothing).


As always, Dell offers an excellent machine at a relatively low price. The unit runs the fastest CPU and has a VGA display which will suite power users. It offers excellent expandability, dual wireless and lots of memory for storage. Your data is safe even if the battery runs down. Not only that, it's attractive and feels good in the hand.

Pro: Overall, a very good device. Attractive and ergonomic design, good price, VGA display, fast processor, both CF and SD slots with SDIO support for the SD slot, Bluetooth 1.2, WiFi 802.11b and VPN support.

Con: WM5's persistent storage architecture means that the device is a bit slower launching programs than older Pocket PCs. Standard battery capacity is lean: consider the extended battery. The screen isn't as nice or as large as the iPAQ hx4700 nor is current 2D graphics performance as good. But the Dell costs less and we may see driver improvements in the future. Device sometimes doesn't wake up when the power button is pressed, requiring a soft reset to reboot. Bluetooth profiles are limited.

Web Site:

List Price $499



Display: Transflective TFT color LCD, 64K colors, screen size diag: 3.7", resolution: 640 x 480, VGA. Intel 2700G graphics processor with 3D acceleration and 16 megs of video memory.

Battery: Lithium Ion rechargeable. Battery is user replaceable. 1100 mA. 2200 mA extended battery available for purchase.

Performance: Intel XScale PXA270 624MHz processor. 64 MB built-in RAM ~ 50 megs available. 256 MB NOR Intel StrataFlash Flash ROM with195 available to store programs and data.

Size: 4.7 x 2.9 x .7 in. Weight: 6.2 oz.

Audio: Built in speaker, mic and 3.5mm standard stereo headphone jack. Can accept 3-ring 3.5mm stereo + mic headsets. Voice Recorder and Windows Media Player 10 Mobile included for your MP3 pleasure.

Networking: Integrated WiFi 802.11b and Bluetooth 1.2.

Software: Windows Mobile 5.0 operating system. Microsoft Mobile application suite including Mobile versions of Word, Excel, PowerPoint, Internet Explorer, and Outlook. Also, Terminal Services, MSN Messenger, Pocket Windows Media Player 10, and Voice Recorder as well as handwriting recognition. 3rd party and Dell software: Resco Picture Viewer, Dell Diagnostic Utility, WLAN (WiFi manager), Enigmo (game), Fathammer's Toy Golf (game), GeoRally (game), Funk Odyssey VPN Client, Data Backup. ActiveSync 4.0 and Outlook 2002 for PCs included.

Expansion: 1 SD (Secure Digital) with 4 bit data bus supporting SDIO and SDIO Now!. 1 CF type II slot that works with type I and type II CF cards. IR port.


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