HP LH4r HP Server - Why buy HP memory? - Page 2

Can Memory from Third Parties Be Used for Server Applications? A large number of third-party manufacturers offer inexpensive memory for PCs. This memory is readily available from a variety of sources, including your local computer superstore. Most of it is intended for desktop PCs in the home or office, but some vendors actively promote their memory as being also suitable for servers. The problem with memory supplied by third-party vendors is that much of it is designed and manufactured for the less-demanding reliability levels required for desktop PCs. For many third-party memory vendors, quality and reliability are of secondary importance. Some of these vendors view DRAMs simply as a commodity and will readily purchase from the chip manufacturer offering the lowest price. On the other hand, HP and other large OEMs have experienced that DRAMs are in fact not a commodity and that there are significant deviations in product quality from one chip manufacturer to another. Table 1 lists typical problems found with memory as a result of inadequate qualification testing, poor manufacturing and design techniques, and nonexistent quality control. Problem Broken or missing decoupling capacitors DRAMs not adequately grounded; copper traces poorly placed and routed DRAMs sensitive to unstable signal from chipset during don't-care states Presence detect improperly configured or not configured at all Use of incompatible DRAMs Improper routing of module board shape resulting in misaligned connectors Poor-quality solder joint Potential Consequence DRAM vulnerable to damage from power supply spikes and surges Poor DRAM performance due to noise and cross-talk, resulting in increased possibility of bit errors Single, double, and multi-bit errors Misinforms the processor of the speed of available memory System failure due to timing errors and other miscellaneous consequences Electrical short causing burn damage to server at module/memory slot junction Long-term failure after continuous operation in hightemperature environment In order to check the viability of alternative memory sources, HP purchased memory labeled as "suitable" for HP NetServers from five different memory vendors, including several very prominent third-party brands. After careful evaluation, products from all five of the memory vendors demonstrated problems found on this list. Although memory products in our sample were functional in the most basic sense, the affected modules had defects that could lead to long-term problems after extended operation. 2