One way of allocating virtual addresses to memory modules is to divide the memory space into contiguous blocks. The CPU can access alternate sections immediately, without waiting for memory to catch up (through wait states). Interleaved memory is one technique for compensating for the relatively slow speed of dynamic RAM (DRAM). Other techniques include page-mode memory and memory caches.
Interleaved memories are the implementation of the concept of accessing more words in a single memory access cycle. This can be achieved by partitioning the memory e.g. into N separate memory modules. Thus, N accesses can be carried out to the memory simultaneously.
from : http://en.wikipedia.org/wiki/Interleaved_memory
內存交錯（Memory interleave）提升了對大內存的訪問速度
SPARC Enterprise M3000及以上型號使用內存交錯技術。並行地訪問多個內存芯片可改進內存的訪問性能。在需要處理大量數據的應用中，該功能尤其有效。
在典型的服務器系統中，大量連續的內存訪問可能是性能瓶頸，因爲內存訪問時延會帶來等待時間。
SPARC Enterprise 的內存交錯功能可並行閱讀大內存芯片，減小內存訪問時間。
內存交錯功能最多可並行訪問單CPU內存板上的 32 個內存芯片。
reference:
Interleaving is an advanced technique used by high-end motherboards/chipsets to improve memory performance. Memory interleaving increases bandwidth by allowing simultaneous access to more than one chunk of memory. This improves performance because the processor can transfer more information to/from memory in the same amount of time, and helps alleviate the processor-memory bottleneck that is a major limiting factor in overall performance.
Interleaving works by dividing the system memory into multiple blocks. The most common numbers are two or four, called two-way or four-way interleaving, respectively. Each block of memory is accessed using different sets of control lines, which are merged together on the memory bus. When a read or write is begun to one block, a read or write to other blocks can be overlapped with the first one. The more blocks, the more that overlapping can be done. As an analogy, consider eating a plate of food with a fork. Two-way interleaving would mean dividing the food onto two plates and eating with both hands, using two forks. (Four-way interleaving would require two more hands. :^) ) Remember that here the processor is doing the "eating" and it is much faster than the forks (memory) "feeding" it (unlike a person, whose hands are generally faster.)
In order to get the best performance from this type of memory system, consecutive memory addresses are spread over the different blocks of memory. In other words, if you have 4 blocks of interleaved memory, the system doesn't fill the first block, and then the second and so on. It uses all 4 blocks, spreading the memory around so that the interleaving can be exploited.
Interleaving is an advanced technique that is not generally supported by most PC motherboards, most likely due to cost. It is most helpful on high-end systems, especially servers, that have to process a great deal of information quickly. The Intel Orion chipset is one that does support memory interleaving.