updated 04:30 pm EDT, Mon March 30, 2009
Intel Nehalem Xeons
Intel this afternoon finally made its Nehalem-based Xeon processors available to a wider audience. First introduced in the Mac Pro, the single-socket Xeon 3500 (not used by Apple) and the dual-socket Xeon 5500 share the same roots as Core i7 and drop the old northbridge system controller and system bus in favor of a point-to-point architecture known as the QuickPath Interface that talks directly to memory and peripherals. The memory controller is now built-in and can talk to three memory channels, improving bandwidth even as it drops lag.
They also add support for HyperThreading, which potentially runs as many as eight program instructions at once on a quad-core processor. For apps that don't depend on heavily parallel code, a Turbo Boost feature that dynamically shuts down unused cores but ramps up clock speeds on the remaining cores. Both moves let ordinarily lower-clocked Xeons at times outperform the earlier 5400 and 3300 models.
The Xeon 5500 line's bulk prices range from $188 for a 1.86GHz dual-core part up to $1,600 for a 3.2GHz quad-core example. Xeon 3500 models are currently limited to just three models between 2.66GHz and 3.2GHz, but their reduced tolerance for multiple sockets lets Intel drop the prices to $284 for the base CPU and $999 for the 3.2GHz version.
While Apple was the first to get access to the processors, Dell has just recently started offering Precision systems with the new chips, while HP's new Z800 tower also uses the faster technology.