Memory Modules FAQ

GENERAL COMPATIBILITY QUESTIONS

  1. I've been told memory modules need to be installed in pairs. Is this true?
  2. Can I use PC-133 memory on my PC-100 system?
  3. My motherboard supports SIMM and DIMM modules. Can I mix the two types together?
  4. Can I mix EDO and SDRAM memory?
  5. My motherboard supports DDR and SDRAM memory modules. Can I mix the two types together?
  6. The manual says my computer can use (X Amount) MB modules. Does this mean any (X Amount) MB modules will work?

TROUBLESHOOTING

  1. My system does not POST (no display on the monitor when power is turned on) after I've installed the memory module. How can I fix this?
  2. My system does not register the entire capacity of the memory module. How can I fix this?
  3. I added more memory to my system, but I still get warnings that my system resources are low. How can I fix this?
  4. I added more memory my system, but now I get "Out of Memory" error messages in Windows. How can I fix this?
  5. The memory module I installed failed the Norton Utilities memory test? Did I receive a defective part?

Q: I've been told memory modules need to be installed in pairs. Is this true?
A: It depends on what types of modules and what types of system you have. SIMM modules are 32 bits wide, while DIMM modules are 64 bits wide. Pentium class processors and above, including current Pentium 4 and Athlon processors, have a 64-bit wide data path to system memory. Therefore, in systems with such processors, SIMM modules, if supported, must be installed in matched pairs. On the other hand, a similar system with DIMM support can have DIMM modules installed singly.

Recently, dual-channel DDR platform systems, which adds a second 64-bit data path to system memory, have been introduced. With two data paths to memory, such systems require the installation of DDR DIMM modules in matched pairs.

Q: Can I use PC-133 memory on my PC-100 system?
A: In general, yes. PC-133 is faster than PC-100, which is faster than PC-66. In most cases you can use faster memory than is required by your system. For example, PC-133 and PC-100 can be used in a PC-66 system. The faster memory will operate at the slower speed. However, you cannot use memory that is too slow for your system, so PC-66 will not be compatible with PC-133 or PC-100.

Q: My motherboard supports SIMM and DIMM modules. Can I mix the two types together?
A: Please check with your motherboard documentation or contact the motherboard manufacturer. In general, the two types cannot be mixed.

Q: Can I mix EDO and SDRAM memory?
A: EDO and SDRAM are different technologies. Please check with your motherboard documentation or contact the motherboard manufacturer to see which type is supported, and if both are accepted whether a mixed configuration is supported. In general, it is better to have all modules of the same type of memory.

Q: My motherboard supports DDR and SDRAM memory modules. Can I mix the two types together?
A: No, DDR (Double Data Rate) and the older SDR (Single Data Rate) SDRAM are not compatible with one another. If your motherboard have DIMM sockets for both types, you must choose to go with one or the other.

Q: The manual says my computer can use (X Amount) MB modules. Does this mean any (X Amount) MB modules will work?
A: Not always. As technological advances allow for modules of greater capacities to become available, memory IC components (the black DRAM chips) must increase in density in order to support the higher capacity modules. DRAM manufacturers often gradually phase out older, lower density components in support for the newer higher density components. Most current memory modules consist of high-density components, which is not compatible with older computer systems that were designed at a time when technology could not support high-density components. Older computers often require low-density components.

Q: My system does not POST (no display on the monitor when power is turned on) after I've installed the memory module. How can I fix this?
A: Here are some options you can try:

  1. Make sure you have the correct type of memory module for your system. For example, 168-Pin DIMMs can feature EDO or SDRAM memory, so be sure you have the correct type.
  2. Make sure the module does not exceed the maximum capacity supported by your motherboard. For example, if the motherboard documentation states that a maximum of 384MB is support and there are three DIMM slots, then you should use 128MB per module.
  3. Make sure the module is firmly seated in the slot with the clips locked in. Clean away any dust to ensure good contact between the module and the slot.
  4. Make sure the processor and graphics card are firmly seated. They may have been accidentally dislodged by you while installing the module.
  5. Check that each module installed on the motherboard is not defective and are not in conflict with one another. Test by first removing all modules from the motherboard. Install each module by itself on the motherboard and try to boot the system. If everything appears to work properly, then install one module, then add back the remaining modules one at a time, booting up the system between each addition, to find the source of the conflict.

Q: My system does not register the entire capacity of the memory module. How can I fix this?
A: There are several reasons that may be causing this:

  1. If the system memory appears to be off by several megabytes, then check to see if you have an on-board graphics processor on your motherboard. Often, on motherboards with integrated VGA, a portion of the system memory, such as 8MB, is placed aside for video memory.
  2. If the system is recognizing only a fraction, such as 1/2 or 1/4, of the total capacity of the module, then the problem is most likely due to your using modules with memory IC's, the black chips on the module, that are too high in density. Many older systems require lower density memory parts. As memory modules with higher megabytes are developed, the density of the memory IC's also must increase. Older, lower density memory parts are phased out and become harder to find. As a result, Quadrant, and most other memory module manufacturers, no longer make modules with such lower density parts. Current modules with high density memory components may not work with the older systems.

Q: I added more memory to my system, but I still get warnings that my system resources are low. How can I fix this?
A: System resources and system memory are not the same thing. System memory refers to the physical memory installed on the system, e.g if you have a 128MB module installed on your motherboard, then you should have 128MB of system memory. System resources are areas of memory used to keep track of the windows that are open and displaying objects on the screen. If this area become full, programs may not load properly and Windows may become unstable, no matter how much free system memory you have. Closing some running applications can free up your system resources, but some software may not release its resources as readily and you may need to reboot Windows.

Q: I added more memory my system, but now I get "Out of Memory" error messages in Windows. How can I fix this?
A: If you system memory is 512MB or above and are running Windows 95/98/Me, please consult Microsoft for the fix.

Q: The memory module I installed failed the Norton Utilities memory test? Did I receive a defective part?
A: If your system has more than 256MB of memory, then this is due to a known bug with Norton Utilities. Please contact Symantec for a fix.

NEED ADDITIONAL HELP?

If you are unable to obtain a solution from the FAQ's, please e-mail Technical Support your questions and a thorough description of your problem. When contacting technical support, please keep the following in mind:

 

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