Intel Launches Xeon 5500 Nehalem-EP

Intel launched the Xeon 5500 series, codenamed Nehalem-EP, in March 2009. The server processors replaced the front-side-bus architecture that had connected CPUs to a shared chipset interface for years.

Nehalem integrated the memory controller into the processor and used QuickPath Interconnect for high-speed links between sockets and I/O. That greatly reduced memory latency and improved bandwidth. Hyper-Threading returned, allowing each physical core to expose two hardware threads, and Turbo Boost raised clock speed when power and thermal conditions allowed.

These changes were especially important in multi-socket servers, where memory access and inter-processor communication can limit performance long before raw arithmetic does. The architecture established many design ideas Intel would use across server and desktop processors for years.