2. 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.