The following are common instances of memory failures and errors:
The POST sounds a single beep code Remember that a single beep code can either sound an all clear or signal a memory failure. If the boot continues, the beep was the all clear. If it stops, check the memory to ensure it is properly installed and is configured in the BIOS properly.
The PC boots with a blank display If the PC is able to boot but the display is blank, it means that an error may have occurred at the beginning of the memory check. The types of conditions to look for are a dislodged expansion card, a memory module not fully seated, or an unsupported memory module. Confirm that all expansion cards and memory modules are seated in their sockets and verify that the memory installed is compatible with the system by checking its part numbers. Putting nonparity RAM in a PC that has error
checking code (ECC) memory,or SDRAM in a PC that supports only EDO (Extended Data Output) memory will definitely cause the boot sequence to halt. See Chapter 7 for more information on memory types..,
The memory count displayed by the POST is wrong If the memory count displayed by the POST is less than it should be, the BIOS isn't recognizing all of the installed memory. A wrong memory type being installed is a common cause for this error, as well as memory banks not being completed. Another problem is incompatible memory or more memory than the system is able to address.
The PC displays a memory error message, such as:
Memory mismatch error
• Memory parity interrupt at nnnnn
• Memory address error at nnnnn
• Memory failure at nnnnn, read nnnnn, expecting nnnnn
• Memory verify error at nnnnn, where nnnnn is the physical address in RAM of the memory fault.
These errors typically point out problems between old memory and new memory or a failing memory module. If removing a newly installed memory module eliminates the error, replace the old memory with the new memory. If the error shows up again, the new memory is either defective or not compatible with the system. Another cause for these messages can be a motherboard problem.
ESD damage Intermittent memory problems those that show up sporadically as an error message, system crash, or a spontaneous system reboot have a number of possible causes, but one of the leading suspects should be ESD (electrostatic discharge). If you are not properly grounded with effective ESD protection when working inside the system unit, you can cause enough damage to either completely fry a component or to create intermittent problems that result from the circuit slowly degrading over time. Other problems for intermittent memory problems are overheating, corrosion, or a faulty power supply.
Software related memory problems The problems under this category include registry errors, general protection and page faults, and exception errors. Registry errors happen when the Windows operating system writes parts of the registry to a defective portion of RAM. Software bugs cause faults and exception errors. For example, an application may release its memory when completed or it may try to occupy the same memory address as another. Rebooting the PC usually solves these problems.
