Tom Krazit covers the basics here--new PowerEdge servers powered by more energy efficient Intel dual-core Xeon (Dempsey, followed by Woodcrest) chips and fully buffered DIMMs, similar to to what other server vendors (especially market leader HP and IBM) will deliver.
I asked Anderson, who joined Dell last year after almost a decade at HP, exiting as senior vice president and general manager of HP's Industry Standard Servers business, about the "details" and what was unique for the new servers beyond packaging the latest industry standard components.
He pointed to new features, such as a programmable LED display for status messages so that technicians can look across the racks and see what is going on without sitting at a management console. (All the lights are red--battle stations!) Other features he mentioned were common power supply placement, an enhanced bezel, a universal drive carrier with a metal brace to dissapate heat and increase stability, new management software, tool-less access to server components, a single system image for the various new servers, and better instrumentation for other management systems.