Things are getting exciting on the computer server front.

For a couple of years, an Austin, Texas-based startup called Calxeda (formerly Smooth-Stone) has been making the case for energy efficient servers using ARM processors — that currently dominate the smartphone and tablet markets — as it prepared to commercialize its tech. Now it looks like the company has found a powerful ally in getting its hardware into data centers.

According to a Wall Street Journal report, HP and Calxeda are partnering to offer ARM-based servers to data center operators and cloud providers — oftentimes one and the same — where low power use and compact physical footprints are emerging as big selling points.

Calxeda isn’t alone in the ARM server race. ZT Systems and Marvell have also set their sights on a market dominated by x86 processor technology from Intel and AMD. But HP’s support, even at this early stage, is a form of validation for Calxeda’s strategy.

It’s also some of the strongest evidence yet that the market is finally ready for servers that won’t put data center operators at a power consumption disadvantage as they scale up to meet massive “cloudy” workloads. According to the WSJ report, sources claim that “compared to mid-range Intel server processors, Calxeda’s chips consume about 90% less energy, take up about 90% less space and have a lower overall cost of ownership.” That’s a pretty compelling selling point.

Lending some substance to these “leaks” are cryptic tweets from Calxeda’s Twitter stream hinting at “Big news from @Calxeda coming soon.” (source) and “Change is in the air. And we don’t mean fall colors.” (source)

The companies are expected to unveil a prototype soon, but don’t expect waves of HP/Calxeda hardware in the immediate future. Volume production isn’t scheduled until the second half of 2012.