1) Rambus dram 
Direct Rambus DRAM or DRDRAM (sometimes just called Rambus DRAM or RDRAM) is a type of synchronous dynamic RAM. RDRAM was developed by Rambus inc., in the mid-1990s as a replacement for then-prevalent DIMM SDRAM memory architecture. RDRAM was initially expected to become the standard in PC memory, especially after Intel agreed to license the Rambu...
Rambus DRAM
Rambus DRAM - A DRAM architecture that has a huge amount of memory bandwidth, however has a high latency penalty. RDRAM is best suited for processors that need high bandwidth like Pentium 4 processors.