Troubleshoot Memory

Troubleshoot Memory
In the last topic, you resolved problems with power supplies. Memory issues can also be the cause of generalized computer problems. In this topic, you will troubleshoot memory.
Memory plays a huge role in every operation done by a personal computer. An issue with memory can result in a wide range of problems and symptoms. As an A+ technician, your abil- ity to identify and solve memory problems will be crucial in providing your users with the optimal computing environment.
Error Checking
Many memory modules include error-checking mechanisms to protect data. The most common are parity and Error Correcting Code (ECC).

Common Memory Issues
Memory problems typically show themselves as memory-specific errors, erratic behavior of the system, or frequent crashes.

Symptom
Computer crashes or reboots; data is corrupted.

Possible Causes
ESD, overheating, or other power-related problems that can affect memory. Registry writing to bad memory, General Protection Faults (GPFs), and exception errors caused by software and operating system.

Symptom
Memory errors appear on screen.
Computer appears to boot; screen remains blank.
Computer does not boot. POST beep codes sound.
Some or all newly installed memory is not recognized.

Possible Causes
Memory address errors at boot time. Memory mismatch errors in which you are prompted to specify how much RAM is installed to clear the message. Applications that require large amounts of memory or that don’t properly release memory.
Memory is not correct for the system. For instance, the computer is expecting memory that uses error checking and you installed non-parity memory. Memory module is not fully inserted into the slot.
CPU cannot communicate with memory due to the memory being improperly installed or the BIOS not recognizing the memory. Beep codes are specific to the BIOS manufacturer and the ones for memory can be found in the manufacturers’ beep codes list.

You exceeded the maximum amount of RAM that can be addressed by the system. Even though the slots can accept SIMMs containing more memory, the system can only recognize a certain amount of memory on most systems. The wrong memory type was installed. The memory was not installed in the proper sequence. You might need to leave empty slots between multiple modules, or you might need to install modules contain- ing more memory in lower-numbered slots than smaller modules.

How to Troubleshoot Memory
Procedure Reference: Troubleshoot Memory Problems
To troubleshoot memory problems:

1. Perform a virus scan. Viruses can cause symptoms that mimic those of a memory problem.
   
2. Verify that the correct memory modules were installed in the system. You can check the part numbers against the memory or PC manufacturer’s website. For example, be sure that you aren’t trying to use DDR2 RAM in a DDR RAM system.
   
3. Verify that the memory was installed and configured properly. Older systems required that memory be installed in pairs. In all cases, verify that the memory modules are fully seated. Always start with memory in the first bank. Check your documentation for other requirements specific to your system.
   
4. Try swapping the memory between slots. For example, if you only experience problems when many applications are open, the chance is that one of the memory modules in the higher banks is the problem. If the system won’t boot, try one of the other modules in the first bank to see if it then boots. Try putting a known good module in the first slot and removing all of the other memory modules.
   
5. Check for BIOS upgrades. If there are known problems, then a fix has probably been issued. This usually applies to older systems.