A dual mode memory module includes an interface configured to receive a first memory module, a first control circuit for switching between unbuffered and registered/buffered modes, an interface configured to receive a second memory module, and a second control circuit for switching the operation of the...http://www.google.com.hk/patents/US6633948?utm_source=gb-gplus-share專利 US6633948 - Stackable dual mode (registered/unbuffered) memory interface cost reduction
