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VGA PDA: Dell Axim X50v

Date: 31.12.2004

The PDA Transformation: From Mobile Pocket Calendar To Multimedia Mobile Device

Handhelds like the X50v also serve as excellent mobile sound systems
Handhelds like the X50v also serve as excellent mobile sound systems

Today's PDAs purport to do a lot more than simply manage your appointments. The motivation of various manufacturers in expanding PDA functionality is no secret: sales figures have been falling sharply for several consecutive quarters. Multifunctional devices represent an attempt to stem the downward tide, and to make the pocket PC appeal to a far broader target group than was the case a year ago.

PDAs such as the Mypal A730 from Asus feature goodies like integrated digital cameras. HP trumps even that with its Ipaq rx3715, luring would-be buyers with WLAN and AV streaming, and touting the device as a multimedia control and play center.

Dell would like to jump into the fray as well, with its top-of-the-line X50v. While the Texas-based engineers at Dell didn't put a digital camera in the new X50 series, they are hoping that the 3.7" VGA screen and dedicated graphics controller - the Intel 2700G Multimedia Accelerator - will jumpstart sales. These features only come with the top model X50v, at a price tag of $425.

The two smaller models, the Axim X50/520MHz and X50/416MHz, have to make do with a QVGA display and no dedicated graphics controller. The midrange Axim X50/520MHz has integrated WLAN and Bluetooth like the X50v, while the barebones X50/416MHz features only a Bluetooth module and half the ROM (64MB). The prices are appropriate to the features, at $339 and $254 respectively.

Before we turn our attention to the X50v and its benchmark results, we'd like to introduce you briefly to Intel's 2700G Multimedia Accelerator.

The 2700G Multimedia Accelerator

The operation of the 2700G Multimedia Accelerator is best explained by taking a look at the block diagram of the chip and the PDA system platform.

Block diagram of the 2700G
Block diagram of the 2700G

From this you can see that the 2700G is a graphics chip that adds 2D and 3D accelerator functions to the PDA. Other special attractions include a small on-die video memory - 704 kB for the 2700G5, or 384 kB for the 2700G3 - and dual-display mode.

In order to enable 3D acceleration, the component features a rendering pipeline implemented as dedicated hardware. Intel claims that it can process 831,000 triangles per second with a pixel fill rate of 84 million pixels - values that look rather modest compared to those of even halfway modern graphics cards. Besides 2D functions such as alpha blending and 2D clipping, the chip supports 3D functions including:

  • Texture and light mapping
  • Bilinear, trilinear and anisotropic texture filtering
  • Texture compression
  • Smallscreen, offscreen and backface culling
  • Fullscreen antialiasing

The video accelerator unit of the 2700G also handles the computation-intensive work of decoding MPEG1/2/4 and WMV videos, handling inverse zig-zag, inverse discrete cosine transformation and motion compensation. That not only helps lower the CPU load, freeing up extra capacity for other tasks, it also reduces the system bus load. During video playback, for example, the motion compensation is calculated in the 2700G's memory, so the operation doesn't tax the system bus.
 

Video accelerator unit of the 2700G
Video accelerator unit of the 2700G
 

Block diagram of a PDA consisting of a PXA27X CPU and a 2700G graphics/video accelerator
Block diagram of a PDA consisting of a PXA27X CPU and a 2700G graphics/video accelerator

Benchmark Anomalies Due To Higher Resolutions And 2D/3D Graphics Accelerator

Using 2D/3D accelerators and VGA resolutions in a PDA has its consequences when running benchmarks, or rather, when interpreting their results.

The first issue is that the benchmarks currently available are written for PDAs with a display resolution of 240x320 (QVGA). If they are run on PDAs with higher resolutions, the operating system has to more or less translate the image output into a VGA resolution. The resulting process overhead for the operating system would seem to suggest that the graphics subsystem of a VGA-PDA is significantly slower. In fact, however, it's the operating system that "eats up" all that time with rescaling, not the graphics hardware.

The second factor is that the functions and benefits of a graphics accelerator like the 2700G can be exploited in real life only if the developer uses programming interfaces like Open-GL ES or DirectX Mobile when designing the applications. That's because their function libraries help utilize the chip's features. If the developer uses standard programming interfaces like GAPI when writing the application, systems with a dedicated graphics chip fare even worse than those without one in some benchmark results. The reason lies in the way the frame buffer is approached: software developers in the "GAPI world" often work by accessing the frame buffer directly using what's known as DFB (Direct Frame Buffer) accesses.

 DFB access path in PDAs with no dedicated graphics chip
DFB access path in PDAs with no dedicated graphics chip

In a PDA with no dedicated graphics chip, the CPU will logically write the frame-buffer content to the on-die memory, if there is one, or to the system RAM otherwise. These accesses can occur very rapidly, depending on the architecture, and on-die memory of course works faster than the system RAM. Graphics benchmarks based on this principle measure the bandwidth between the CPU and the graphics memory.

When a graphics controller is available, however, the content of the frame buffer will be written to the on-die memory of either the graphics chip or its video memory.

DFB access path in PDAs with dedicated graphics controller
DFB access path in PDAs with dedicated graphics controller

If a benchmark based on the CPU's DFB access is run on this kind of system, the results will appear to be worse than they should be. That's because it naturally takes longer for the CPU to access the on-die memory of the graphics chip or its video memory than it does for it to access the CPU's internal memory or the system memory. But it would be wrong to conclude that the graphics performance of this type of system is inferior; the processor access to video memory is just slower.

After that brief excursion into the benchmark problems associated with new system architectures, we'd now like to present the Axim X50v - in living color.

The X50v In Pictures

With the Axim X50 series, Dell has finally given its pocket PCs a visually more appealing, slimmer and curvier design. The case would be truly perfect if Dell had opted for metal instead of plastic as the construction material - it seems that fierce price wars are taking their toll in this segment, too.

In a direct comparison with the Axim X30i, the X50v is more attractive
In a direct comparison with the Axim X30i, the X50v is more attractive

The button for activating the Bluetooth and WLAN modules is now located on the left side of the device; below it is the on/off switch for the voice recorder. Above these two buttons is the new hold slider switch with which you can deactivate all function buttons, and the pen input. The hold feature makes sense if you use your PDA as an MP3 player, for example.

The X50v In Pictures

We found the position of the wireless radio button to be a rather poor choice, as you're bound to accidentally push the button now and again when you hold the unit in your hand to use it. On the flip side, we experienced no problems with the Bluetooth connection to various headsets during the test. The internal WLAN module likewise communicated flawlessly with numerous access points from several providers.

Anyone who thinks the X50v's internal working memory (128MB ROM/64MB RAM) is too small can boost the storage capacity with a SD or CF card. The corresponding slots are located on the top edge of the unit.

The X50v In Pictures

The microphone is located on the top left. A single LED in the top right corner signals the operating mode of the wireless modules, flashing blue and green if the BT and WLAN modules are on. If you deactivate one of these, the LED only flashes in one color, corresponding to the device still in use.

The circle on the left indicates the microphone; the one on the right, the LED for the wireless radio status.
The circle on the left indicates the microphone; the one on the right, the LED for the wireless radio status.

The X50v In Pictures, Continued

Included in the box with the Axim X50v is a cradle that doubles as a charger for the optional additional standard battery (1100mAh, $50) or high-capacity battery (2200mAh, $90).

The X50v In Pictures, Continued

We view the high-capacity battery as a sensible investment, as the battery benchmarks below illustrate. The X50v's battery is housed under a door on the back of the unit.

The X50v In Pictures, Continued

You don't have to lug the USB cradle with you when you travel; the X50v can also be charged directly from a power outlet using the supplied AC adapter. If you do this, you need a notebook with a BT module so you can synchronize data with the Axim X50v.

In conjunction with the power pack, this adapter keeps the handheld supplied with power on the road.
In conjunction with the power pack, this adapter keeps the handheld supplied with power on the road.

Although the stylus is quite a bit slimmer than that of the X30, it feels nice in the hand.
Although the stylus is quite a bit slimmer than that of the X30, it feels nice in the hand.

The X50v In Pictures, Continued

While the few included accessories generally make a solid impression in terms of quality, the same cannot be said of the standard slip case.

Cheap look and feel, and impractical to boot: the Axim X50v slip case
Cheap look and feel, and impractical to boot: the Axim X50v slip case

The nylon case proves inconvenient in everyday use, since you have to tuck the device away to protect it. All the fumbling and tugging required whenever you feel like just jotting something down quickly becomes tiresome. Before you know it, you feel compelled to scour the catalog of available extras for a suitable carrying case. Unfortunately, we suspect that this is precisely what Dell intended to begin with by using such a cheap case as an included accessory. :(

All of the above notwithstanding, the most important reason for buying this pocket PC - besides its integrated wireless functions - turns out to be the 3.7" VGA display. Whether you're surfing the web.....

...or using it as a mobile video player.....
...or using it as a mobile video player.....

....or a mobile gaming console....
....or a mobile gaming console....

...a display with a resolution of 480 x 640 pixels makes using your PDA a whole lot more fun. We also judged the display's contrast to be very good; working in bright conditions, including outdoors, was not a problem.
...a display with a resolution of 480 x 640 pixels makes using your PDA a whole lot more fun. We also judged the display's contrast to be very good; working in bright conditions, including outdoors, was not a problem.

Axim X50v Features Table
 

 

Axim X50v
Manufacturer Dell
Technical Data
CPU / Clock PXA270 / 624MHz (520MHz, 208MHz)
System Memory 64MB
3D-/Video-Accelerator Intel 2700G5
Video memory (ondie/dedicated) 704 kB/16 MB
Flash-ROM 128MB
Dimensions 2.80" x 0.65" x 4.60" / 74mm x 16mm x 118mm
Weight 6oz / 170g
Display
Resolution 480 x 640 Pixel (VGA)
Color Depth 65536
Display Size 2.28" x 2.99" / 58mm x 76mm
Hardware
Function buttons 6
Jog dial no
Loudspeaker yes
Keyboard no
Battery
Technology Lithium-Ion
Capacity 1100mAh
Backup-Battery yes
Recharge without Docking yes
Interfaces
Compact Flash Yes
SD/ MMC card yes
Irda/ Bluetooth/ WLAN yes/yes/yes
USB yes (Host/Client)
Microphone yes
Audio out yes
Included in package
Power Adaptor yes
OS Pocket PC 2003 SE
Provided Software Outlook2003, Enigmo,Stuntcar Extreme ClearvueSuite2.41,Monopoly Scrabble, Triptracker, Citytime, eWallet
USB Docking-Station Yes
Protection Case yes (average Quality)

Like all the latest Xscale processors from Intel, the 624MHZ PXA270 inside the Axim X50v features power-saving Wireless Speedstep technology, and the instruction-set extension Wireless MMX. Wireless MMX is meant to make it easier to port multimedia applications to the Windows Mobile PC platform.

We used auto mode for the benchmarks
We used auto mode for the benchmarks

The device lets the user choose from a number of fixed CPU speed settings or have the operating system set the processing speed automatically.

3D Graphics Performance

For the time being, we are not able to quantify just how much of a performance edge the integrated 2700G graphics accelerator gives the Axim X50v in practice. This is due to the fact that there is still no benchmark for PDAs that enables direct measurements of 3D performance or video acceleration. Popular games such as Pocket Quake are based on older graphics interfaces that do not take advantage of the special features of the 2700G.

Stuntcar Extreme highlights the performance bonus provided by the dedicated graphics chip
Stuntcar Extreme highlights the performance bonus provided by the dedicated graphics chip

However, the proof is in the pudding, as they say. What we can say about the 3D performance is that the supplied games, including Enigmo and Stuntcar Extreme, look darned impressive and run very smoothly.

Benchmarks

Due to the abovementioned constraints, we only used two benchmarks in this review. In going with Sisoft Sandra Pro 2004.8.9.131, we chose a benchmark that uses some Wireless MMX commands. PPC Benchmark from our partner PC Professionell Deutschland provides us with additional performance values for the CPU and 2D graphics as well as the battery rundown time.

CPU Performance With Partially WMMX-Optimized Application: Sandra Pro (2004.8.9.131)

CPU Performance With Partially WMMX-Optimized Application: Sandra Pro (2004.8.9.131)

Although no MMX commands are used in the CPU arithmetic benchmark, the fact that the Axim X50v is equipped with the fastest CPU on the market lets it dominate this area.

CPU Performance With Partially WMMX-Optimized Application: Sandra Pro (2004.8.9.131)

The Multimedia Benchmark from Sandra also uses some Wireless MMX commands. In this field as well, the X50v illustrates some advantages over its rivals in the test.

CPU Performance With Non-wMMX-Optimized Application

A non-wMMX-optimized benchmark like the Pocket PC benchmark from our partner PC Professionell measures system performance with a fairly CPU-intensive standard application.

CPU Performance With Non-wMMX-Optimized Application

The top-end model in the X50 series does well here, too, thanks to its high maximum CPU speed.

2D Graphics Performance

2D Graphics Performance

The result here is not surprising, since this benchmark measures the bandwidth between the graphics memory and the CPU rather than actual graphics performance. The bandwidth is lower in a system with a dedicated graphics chip than in a PDA that relies on the CPU to process graphics data in addition to its other tasks. See "Benchmark Anomalies Due to Higher Resolutions and 2D/3D Graphics Accelerators", above, for a more detailed explanation of this phenomenon.

Battery Life

We took various measurements of the battery rundown time with different combinations of activated/deactivated Bluetooth and WLAN transceivers.

Battery Life

As was the case with its predecessor, the results demonstrate once again that the wireless modules should only be switched on if they really have to be used. Running them continuously reduces the battery runtime considerably - and at just under 4.5 hours, the battery life of the Axim X50v doesn't set any standards vis--vis the competition, either. Therefore, anyone contemplating purchasing the X50v should consider ordering the optional high-capacity battery (2200mAh/US$90) right away.

Battery Life

Conclusion: More Modern Than The X30i, But Not Perfect

Dell thinks $425 is a suitable asking price for its newest high-end model the Axim X50v. For the money, the customer receives a powerful PDA with VGA display, dedicated 2D/3D graphics accelerator, a rich feature set, and excellent expandability. The new design represents an undoubted improvement over the "old" X30 series, although the same cannot be said of the battery life, at four and a half hours. A metal casing would have also added a touch of class.

Upon critical inspection, the dedicated graphics chip sounds more impressive than it really is, since current applications (save for the odd game) can't derive any benefits from the theoretically available graphics performance.

Compared with the competition, however, the Axim X50v is nonetheless a good choice, as Asus' VGA PDA with integrated Bluetooth and WLAN functionality, the Mypal A730W, currently sells for $600. Sure, that device also features an integrated 1.2 megapixel digital camera, but it also has far worse battery life. You could also opt for HP's Ipaq hx4700 for $650. Initial measurements gave this pocket PC a battery life on a par with the handheld from Dell, plus it sports touchpad input as a neat feature. Still, we're not convinced that this alone justifies the significantly steeper price.

So just who is the Axim X50v aimed at? Well, just about everyone - consumers and businesspeople alike - who want to buy a fully loaded, relatively reasonably priced PDA with VGA display right now. Die-hards like that won't be deterred by the fact that the device's dedicated graphics accelerator is useless at present, except for the occasional gaming title.

To everyone else, such as folks who only recently bought a fast and well-equipped PDA like the X30i, our advice is: sit tight and wait for the price reductions that are sure to come.

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Copyright 2002 yvind Haugland
Sist endret:  13 januar 2019
 

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