XScale vs. StrongARM PDA – THG.RU

Battling brothers – XScale or StrongARM Processor?

In the market for a new PDA, but don’t know which one to buy? The choice just got murkier. Should you get an expensive model with the latest Intel XScale processor, or can you get by with a cheaper version based on its older brother, the Intel StrongARM processor? The new Intel XScale PXA-250 CPU is already cranking away at 400 MHz in the Asus MyPal A600 and the Fujitsu-Siemens (FSC) Pocket Loox. Yakumo’s Alpha, has to make do with the widely used StrongARM processor SA-1110 and 206 MHz.

The XScale Dilemma: Neither Application Software nor OS Are Optimized

The applications.

Users have grown accustomed to one of the XScale’s quirks: while the 400 MHz clock speed of XScale PXA-250 processors is twice that of the SA-1110, you won’t notice any difference in speed when running your programs. On the contrary, some applications are even a touch slower. The only programs that get any boost from XScale’s architecture are those that work directly with the CPU.

There are a few reasons for this “bizarre” behavior: for one, the Pocket PC 2002 operating system has not been optimized for XScale processors; nor are there any applications available that make use of the advantages of the XScale architecture. We were also unable to prove the claim that XScale processors are less power-hungry than the StrongARM processors.

Development Aid from Intel: Software Optimization Center

Intel wouldn’t be Intel if it hadn’t cooked up a way of solving these “initial difficulties.” In this case, the name of the solution is the “Software Optimization Center” (SOC), opened this summer in Arizona. And since the beginning of October, European application developers can draw on the services of an equivalent facility, based in Stockholm, Sweden, in order to optimize their software. In short, Intel is doing its best to encourage XScale optimization and to increase developers’ familiarity with the IPPs (Integrated Performance Primitives) and the GPPs (Graphics Performance Primitives). The IPPs are optimized libraries that capitalize on the new features of the XScale CPUs for special tasks such as MPEG-4 decoding or voice compression. The GPPs provide appropriate 3D-graphics routines.

XScale architecture is, in theory, much faster and less power-hungry than that of the StrongARM.

Only time will tell whether these efforts will bear fruit. At the moment, we at THG don’t know that any standard application has been proven to run faster on an Xscale system or to consume less electrical power.

XScale Power: Asus MyPal A600

The MyPal A600 in the USB cradle.

Until recently, Asus was known mostly as a manufacturer of motherboards and notebooks. The MyPal A600 is Asus’ first venture into PDA territory. Its first creation is a real beauty, too, with a high-quality metal housing and an extremely thin construction. Weighing in at 134 grams and measuring 75 x 125 x 13 mm, the MyPal A600 won’t be too bulky for your shirt pocket, either.

Left side of the housing: power button, jog dial to navigate the menu, and a record button for voice notes.

The A600 also has a jog dial on the left side of the housing in addition to standard controls like the navigation key and four hotkeys.

The speaker is in an inconvenient location – underneath the navigation key.

On top: IR port, MMC/ SD card slot, headset and microphone jack.

Asus has equipped its pocket PC with only one SD card slot for expansions. However, you may also opt for a CF card adapter that just snaps onto the back, so you can add on WLAN or Bluetooth modules, or even expand memory with an IBM Microdrive.

It’s Not Just Pretty – It’s Fast, Too

But the MyPal A600 isn’t just about its looks. Asus also developed sophisticated CPU settings so you can tweak both power consumption and the performance of your XScale processor.

Asus’ specialty is providing sophisticated CPU settings.

The manufacturer has integrated a control panel option called “Advanced Performance Enhancement,” which makes data caching more efficient and enhances performance. A message appears on the screen, warning you that this could make the system less stable, but we didn’t encounter any problems during the tests. Performance improves by leaps and bounds. For example, it takes much less time to scroll through complex HTML documents. The benchmark readings clearly indicate a jump in performance. While the non-enhanced MyPal needs 5032 milliseconds for the integer benchmark, it only takes 3449 milliseconds with cache optimization.

Users can also control the CPU clock using one of three settings (Turbo, Normal and Power Save modes). In Normal mode, the clock is set to 200 MHz, while the Power Save mode drops the clock to 100 MHz, thus saving battery power. In the 400 MHz mode, the PCpro benchmark calculates a total running time of two hours and 49 minutes. In Power Save mode, the PDA keeps on trucking for over eight hours.

All’s quiet on the display front – the A600 comes with a reflective color display (16-bit color depth) that displays at a resolution of 240 x 320 pixels – standard fare for pocket PCs. The anti-reflection on the display surface is excellent, allowing users to read the screen content even when a light is shone directly on it.

Asus’ first foray into the PPC world is excellent, with lots of power and an attractive design. The only drawback is the price, which is far too high considering it is without a Flash slot or integrated WLAN or Bluetooth modules.

Armed to the teeth – the Pocket Loox

The FSC Pocket Loox seems downright frumpy compared to the sleek MyPal. Looks can be deceiving – it is very well outfitted for expansions, with a Compact Flash and an SD/ MMC card slot, as well as a slot for a WLAN or GPRS module on the back. The Pocket Loox also comes standard with a Bluetooth module (Class 1), which is controlled with the easy-to-use Plugfree program.

Its handling is equally superb. A jog dial is integrated on the left side of the 170 gram PDA, for scrolling and clicking. Pressing an additional switch on the left edge opens a special menu that you can flick through with the jog dial to access the most essential functions.

The battery run time is not as good: the Loox hangs on for a paltry three hours in power save mode and with a reduced clock speed. At a more normal clock (400 MHz), the lights go out after as little as 120 minutes, despite the fact that the device doesn’t exactly break any records in the integer benchmark – 5249 milliseconds.

The Yakumo Alpha Reigns in Running Time

The German microcomputer company Vobis has produced the first B-brand pocket PC, the Yakumo Alpha, which is also one of the cheapest devices on the market. However, the Yakumo Alpha doesn’t offer any wireless technologies like Bluetooth or Wireless LAN. The plastic casing is covered in a silvery cobalt blue that makes it look like a poor cousin to the competition. The four quick-start keys on the front are a tad too small. The manufacturer has omitted a navigation key entirely, choosing instead to integrate a jog dial on the left side of the casing for scrolling. The telescopic pen for the touchscreen is a real eyecatcher: it’s only two-and-a-half inches long pressed together; pulled out, it measures around four-and-a-half inches. The Alpha is expandable, with an integrated MMC/ SD slot and a Compact Flash expansion module that clicks onto the back.

On top: IR port, MMC/ SD card slot, headset and microphone jack.

It doesn’t really matter that this PDA can only be charged in a cradle: after all, it ran a good eight hours off its batteries – there’s no need to constantly recharge it. Don’t go on a trip without the docking station and cables, though. The two other test candidates can be charged without the docking station. As if to compensate, Yakumo has designed the Alpha with a removable battery – a rarity in the PDA world. You can charge a back-up battery in the cradle alongside the normal one. If you don’t mind the Yakumo Alpha’s clumsy looks and aren’t keen to having integrated wireless communication, this PDA is the one for you. No other competing device can beat it for high performance, low price and long battery life.

Put to the Test: The PDA Benchmark

For the first time, THG has used the PDA benchmark of our cooperation partner PC Professionell to rate the performance and battery life for each of the devices. The benchmark derives the performance score from three factors that are relevant to the power of a pocket PC and that are the smallest common denominators of all three devices: CPU performance, 2D graphics performance and data throughput.

CPU Performance: Integer, Floating-Point and Heap Management

The Pocket PC Benchmark calculates CPU speed using two different algorithms. One measures how swiftly the processor performs integer commands; the other, floating-point commands. Dynamic memory management performance (heap) is determined using a third algorithm.
CPU Performance: Integer Arithmetic

The algorithm used in this test is based on the sieve algorithm. This algorithm, also known as the “Sieve of Erastothenes,” calculates prime numbers. This gives you insight on how quickly the CPU can perform random access commands for the main memory. The calculated value specifies how long the PDA needs to calculate the prime numbers.

With its CPU Turbo mode, the MyPal A600 managed to stay several steps ahead of the competition in this discipline.

CPU Performance: Floating-Point Arithmetic

This section of the benchmark calculates a mathematical formula using a constant series of random numbers. The benchmark measures how long the calculation lasts.

The MyPal A600 scores higher than the Pocket Loox in this test, as well. The slower clock on the Yakumo Alpha’s StrongARM CPU forces it to take the booby prize.

CPU Performance: Heap Management

In heap management, the benchmark measures main-memory management using the recursive Fibonacci function. The Fibonacci algorithm invokes itself recursively to calculate the result, testing the management of the dynamic memory (heap).

It was a head-to-head race between Pocket Loox and Asus MyPal, with neither emerging a clear winner.

Performance: 2D Graphics

The graphics benchmark also consists of three subroutines that display geometric figures such as ellipses, rectangles and polygons, using Windows CE’s GDI (Graphic Device Interface). As the GDI is the basis of all Windows programs, it is a meaningful factor in evaluating graphics performance. It measures the time needed to “draw” different geometric figures.

The Pocket Loox from FSC performs the best in this test.

Data Throughput

The benchmark calculates data throughput by continuously writing and reading a 1 MB file.

Battery Runtime

The battery test integrated in the PDA benchmark determines how long the pocket PC requires to reach the critical 30-percent limit of remaining battery capacity. Microsoft has stated that data integrity cannot be guaranteed below this threshold. The test performs a virtual pen movement on the display every five seconds so that the pocket PC doesn’t shut off. The device’s status is logged in a report file every 60 seconds. To keep results consistent, the display brightness of each pocket PC must first be set to the same value (30 candelas per square meter).

The Pocket Loox desperately needs to have its power management improved. Asus’ MyPal A600 shows that PDAs don’t have to be wasteful.

Practical Test: Synchronizing Contact Information

In this practical test, we synchronized the Contacts folder on the PDA via its USB cradle with a Contacts folder on a PC that held 1,800 contacts. We used Outlook 2002 under Windows XP Professional as a PIM.

The PDAs in Brief

Conclusion: The Future Belongs to XScale – Probably

As Asus has clearly shown with its MyPal A600, it is possible to build elegant, powerful and long-winded XScale PDAs.

The full-featured Pocket Loox from FSC demonstrates – on behalf of the bulk of the current stock of XScale pocket PCs – the downsides of the first-generation devices. The new PDAs have much shorter battery runtimes at the same display brightness than much slower-clocked devices with StrongARM CPUs. Users have yet to reap any benefits from the faster CPU clock, since there are precious few optimized applications. At the moment, the main thing in favor of the XScale devices is that they are future-proof. However, the balance may tilt in favor of the XScale products in the next several months, once Intel’s Software Optimization Initiative takes hold.

Of course, in some situations, PDAs with StrongARM CPUs may still be the better buy. If you don’t want a device for the long haul, but would prefer not to unload too much money, the long-winded and inexpensive Yakumo Alpha may very well be the PDA for you.