Dell Axim X50v
VGA PDA: Dell Axim X50v
Date: 31.12.2004The PDA Transformation: From Mobile Pocket Calendar To Multimedia Mobile Device
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 thepocket PC appeal to a far broader target group than was the case a year ago.
PDAs such as theMypal 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 adigital 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 2700GMultimedia Accelerator is best explained by taking a look at the block diagram of the chip and the PDA system platform.
From this you can see that the 2700G is a graphics chip that adds 2D and3D 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:
Thevideo 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.
Using 2D/3D accelerators and VGA resolutions in aPDA has its consequences when running benchmarks, or rather, when interpreting their results.
The first issue is that the benchmarks currently available are written forPDAs 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.
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.
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.
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 anMP3 player, for example.
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 numerousaccess 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 orCF card. The corresponding slots are located on the top edge of the unit.
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 X50v In Pictures, Continued
Included in the box with theAxim X50v is a cradle that doubles as a charger for the optional additional standard battery (1100mAh, $50) or high-capacity battery (2200mAh, $90).
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.
You don't have to lug theUSB 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.
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.
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 whatDell 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 integratedwireless functions - turns out to be the 3.7" VGA display. Whether you're surfing the web.....
Axim X50v Features Table
Like all the latest Xscaleprocessors 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.
The device lets the user choose from a number of fixedCPU 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 2700Ggraphics 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.
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.
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 someWireless 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)
Although no MMX commands are used in theCPU arithmetic benchmark, the fact that the Axim X50v is equipped with the fastest CPU on the market lets it dominate this area.
TheMultimedia 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 thePocket PC benchmark from our partner PC Professionell measures system performance with a fairly CPU-intensive standard application.
The top-end model in the X50 series does well here, too, thanks to its high maximumCPU speed.
2D Graphics Performance
The result here is not surprising, since this benchmark measures the bandwidth between the graphics memory and theCPU 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.
We took various measurements of the battery rundown time with different combinations of activated/deactivatedBluetooth and WLAN transceivers.
As was the case with its predecessor, the results demonstrate once again that thewireless 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-à-vis the competition, either. Therefore, anyone contemplating purchasing the X50v should consider ordering the optional high-capacity battery (2200mAh/US$90) right away.
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 powerfulPDA 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 megapixeldigital 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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