Last week Real World Tech published a huge whitepaper with lots of information on Intel's upcoming CSI. This is the long-awaited answer from Intel to HyperTransport.
For everyone with little time ARS Technica summarized the article from Real World Tech and presents you Intel's CSI in a nutshell:
The main draw of CSI is that, like HyperTransport, it's a point-to-point interconnect for multisocket systems that can support an on-die memory controller. When Intel moves to on-die controllers and NUMA in the server market, this will immediately provide a dramatic boost to Xeon systems' aggregate bandwidth—possibly on the order of 8x to 10x. This greatly increased system bandwidth, along with Intel's projected move away from power-hungry FB-DIMMs, will help with Xeon systems' current power/performance deficit versus AMD's Opteron..