HP Professional AP500 Compaq Professional Workstation AP500 Key Technologies W - Page 6

WHITE PAPER (cont'd) Compaq Workstations - Key Technologies MEMORY The Compaq Professional Workstation AP500 uses 100-MHz Registered ECC Synchronous DRAM (SDRAM) and supports up to 1 GB of memory. SDRAM is designed to accommodate higher processor speeds and provides faster memory operation with burst data rates of up to four times that of standard page-mode DRAMs. The new burst mode addresses an entire block of data rather than one piece at a time. Most importantly, SDRAM is synchronized with the CPU system clock to allow continuous data flow. Estimated performance increases are 2% for cached systems and 10% for non-cached systems. 100-MHz SDRAM is required to work with the 100-MHz Front Side Bus (FSB), which is an integral part of high-speed systems. 100-MHz SDRAM is designed to accommodate higher microprocessor speeds and to provide faster memory operation. CUSTOMER BENEFITS There are clear benefits to SDRAM compared to the previous memory technology, EDO (extended data output) DRAM. Some key benefits are: • Increased performance. Customers will experience greater CPU responsiveness with SDRAM technology. The 100-MHz SDRAM will support high-speed Pentium II 400MHz and 450-MHz technologies that EDO DRAM cannot support. • Faster bus speeds. SDRAM can run up to 100 MHz, while the maximum bus speed that EDO DRAM can run is 66 MHz. • Perfect match for demanding applications. As graphics and software programs become more and more complex, SDRAM is better suited to handle these advances compared to EDO SDRAM because of its higher bus speed. Q. Compaq Professional Workstation AP500 uses registered memory. What is the difference between registered and unregistered memory? A. Registered memory is buffered memory. Buffered DIMMs use buffer logic chips on their control lines to reduce loading on the system board. This buffering action increases the maximum size of DIMM module sockets on the system board. Unbuffered DIMMs do not use any buffer logic chips, thus achieving slightly faster operation due to the elimination of the propagation delay of the logic buffer. The increase in speed comes at the tradeoff of reducing the maximum size of DIMM modules on the system board, which results in smaller memory capacity. Q. Can I use older memory from my installed base of Compaq Professional Workstation systems in the new AP500 machine? A. The Compaq Professional Workstation AP500 uses the same memory as the Compaq Professional Workstation AP400; however, the AP500 memory is not interchangeable with the AP200, 5000, 5100, 6000, or 8000 products. The AP200 uses unregistered DIMMS, and the remaining products use 66-MHz EDO memory. 6