The Intel Xeon E5540 was a server/workstation processor with 4 cores, launched in March 2009, at an MSRP of $774. It is part of the Xeon lineup, using the Gainestown architecture with Socket 1366. Thanks to Intel Hyper-Threading the core-count is effectively doubled, to 8 threads. To further increase overall system performance, up to two Xeon E5540 CPUs can work together in a multi-processor (SMP) configuration. Xeon E5540 has 8 MB of L3 cache and operates at 2.533 GHz by default, but can boost up to 2.8 GHz, depending on the workload. Intel is making the Xeon E5540 on a 45 nm production node using 731 million transistors. The multiplier is locked on Xeon E5540, which limits its overclocking potential.
With a TDP of 80 W, the Xeon E5540 consumes a good deal of power, so decent cooling is needed. Intel's processor supports DDR3 memory with a triple-channel interface. The highest officially supported memory speed is 1066 MT/s. ECC memory is supported, too, which is an important capability for mission-critical systems, to avoid data corruption. For communication with other components in the computer, Xeon E5540 uses a PCI-Express Gen 2 connection. This processor lacks integrated graphics, you might need a graphics card.
Hardware virtualization is available on the Xeon E5540, which greatly improves virtual machine performance. Additionally, IOMMU virtualization (PCI passthrough) is supported, so that guest virtual machines may directly use host hardware.