The first system to feature the X3 will be the eServer xSeries 366 which can use up to 4 of Intel's 64-bit Xeon processors. It will also feature support for the upcoming dual-core Xeon processors. These servers will be available within 3 months and will start selling at approx. $6,000.
The X3 aims to bring more mainframe-like capabilities, such as virtualization, to relatively inexpensive servers based on Intel chips. The move is meant to boost the machines' performance and set them apart from competitors'.More info at ZDNet