Memory-chip designer Rambus will show off faster versions of its DRAM technology in San Francisco this week at the Intel Developer Forum, a confab for computer-hardware designers, the press and other tech mavens. The new RDRAM flavor is called RIMM4200 and is an update of Rambus' RIMM technology--for Rambus inline memory module. It adds a second memory channel and faster new chips to increase the speed at which data moves from the module to other PC components. The RIMM4200 incorporates two 2.1GB-per-second memory channels to transfer data at a combined rate of up to 4.2GB per second, Rambus said. The current Rambus RIMM, the 1600, uses only one channel and offers rates of 1.6GB per second--though many PCs use dual-channel configurations that pair modules to deliver rates of up to 3.2GB per second. The RIMM4200 module also uses new, speedier RDRAM chips running at 1066MHz. The current Rambus RIMM uses 800MHz RDRAM chips. RIMMs are constructed by combining several chips on a circuit board. The move by Rambus comes at a critical time for RDRAM. Though PC makers and Intel say RDRAM continues to offer the highest performance, efforts by Advanced Micro Devices and a new Intel 845 chipset for the Pentium 4 have helped popularize a rival technology known as Double Data Rate SDRAM.