HP Professional sp750 Compaq Professional Workstation SP750 and AP550 Key Tech - Page 7

WHITE PAPER (cont'd) Compaq Professional Workstation - Key Technologies Rambus Technology Developed by Rambus, Inc. in conjunction with Intel Corporation, Rambus DRAM (RDRAM) is a new memory technology designed to keep pace with the latest high-speed microprocessors and graphics controllers. Workstation users demand the ability to quickly and easily navigate tremendous amounts of information, including complex graphics and multimedia content. The Rambus solution achieves a ten-fold increase in component throughput, while utilizing fewer ICs and assuring a modular/scalable solution. A single RDRAM is capable of delivering 1.6 GB/s per channel. It is 2 byte wide running at 400 MHz clock (Data is transferred twice in each cycle − on both the rising and falling edge of the clock. The 800-MHz description in memory modules is referring to both the rising and falling edge of the clock. 2 Bytes * 400M Transfers/s * 2 = 1.6 GB/s.) with 95% efficient memory sub-system and protocol. Customer Benefits • Improves memory bandwidth to improve performance in memory-intensive applications. • Provides headroom to accommodate the fast memory requests of increasingly powerful processors. Hard Drives There are two primary interfaces (between the drive and the workstation system bus) available for drives today, Ultra ATA and SCSI. Compaq offers the highest-performance hard drives available and the choice of Ultra3 SCSI and Ultra ATA/66. Ultra3 SCSI Hard Drives Ultra3 SCSI is the newest generation of SCSI technology utilizing LVD (low voltage differential) signaling and an 80-MHz clock rate to allow maximum burst rates on the Ultra3 SCSI bus of 160 MB/s, which doubles the maximum burst rate of Wide Ultra2 SCSI. This higher data burst throughput rate provides superior performance in large data transfers, such as streaming video, loading large CAD models, and especially in configurations with several high-speed disks on a single controller. The Ultra3 controller offers more bandwidth headroom for these demanding applications than is available on the Wide Ultra2 SCSI controller and older 40 MB/s Wide-Ultra SCSI devices and is therefore more impervious to performance degradation due to saturation of the SCSI bus. LVD also uses differential signaling technology, which has lower voltage swings and is less susceptible to noise than Ultra SCSI technology. 7