A primer on Rambus Memory

Intel on Nov. 15th, 1999 released the i820 chipset (also known as "Camino"). This new chipset, when incorporated into a suitable motherboard and CPU, supports a new type of RAM known as Direct Rambus memory, or RDRAM. With it, Camino and several successive Intel motherboards are able to provide memory speeds of up to 1.6GB/sec. Support for Direct Rambus memory was, for the record, first announced by Intel back in Dec. 1996. This memory supports the 133 MHz bus speed of the latest Pentium III-based systems, but, at least initially, costs substantially more than PC100 SDRAM.

By comparison, DDR SDRAM (sometimes called DDR DRAM), or double data rate Synchronous DRAM, doubles the bandwidth of DRAM in a similar fashion to the way AGP 2x did with AGP. Thus DDR SDRAM provides similar performance to that of RDRAM with lower latency. In each case, you must match the memory with a supporting motherboard.

Intel, prior to July 2000, had stated that its future designs would use RDRAM, although it reversed this position due to market demands. Intel now says it is working on pairing the chipset with DDR DRAM.

The biggest drawback to RDRAM is that its bandwith is limited to 1.6 GB/s due to the design's small 16-bit bus. There is also a great deal of industry debate over the merits of the technology. Critics say RDRAM is overpriced and is yet another example of Intel providing a "solution" that makes competing technologies obsolete. Indeed, Intel in July 2000, announced that its would not require Rambus memory designs for its forthcoming Pentium 4.

In the months ahead, we'll take a closer look at what Rambus and its competitors are all about. For now, though, check out these links as a Rambus primer....