Integrated processing and l2 dram cache

Abstract

An integrated processor and level two (L2) dynamic random access memory (DRAM) are fabricated on a single chip. As an extension of this basic structure, the invention also contemplates multiprocessor 'node' chips in which multiple processors are integrated on a single chip with L2 cache. By integrating the processor and L2 DRAM cache on a single chip, high on-chip bandwidth, reduced latency and higher performance are achieved. A multiprocessor system can be realized in which a plurality of processors with integrated L2 DRAM cache are connected in a loosely coupled multiprocessor system. Alternatively, the single chip technology can be used to implement a plurality of processors integrated on a single chip with an L2 DRAM cache which may be either private or shared. This approach overcomes a number of issues which limit the performance and cost of a memory hierarchy. When the L2 DRAM cache is placed on the same chip as the processor, the time needed for two chip-to-chip crossings is eliminated. Since these crossings require off-chip drivers and receivers and must be synchronized with the system clock, the time involved is substantial. This means that with the integrated L2 DRAM cache, latency is reduced.