1. I have over 64MB of RAM, but DOS can't see it all while Windows can.
2. There is 128KB or 384KB of RAM that is never reported when I boot up.
3. The system is reporting much less memory than is actually in the system.
4. My system seems to have slowed down upon adding more memory.
5. I am getting a memory parity error when I boot up.
6. I am getting parity errors during normal operation of the PC.
7. Receive out of memory error with plenty of memory.
8. Installed Memory but Win XP Pro won't start now.
9. Identify a bad memory module

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I have over 64MB of RAM, but DOS can't see it all while Windows can.

The way that DOS is designed, it cannot see over 64MB of RAM. Almost all of the time, though, any DOS program will not require any more than 64MB anyway. You can try to find a special memory manager, but the thing to do is get with the times and start using Windows.

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There is 128KB or 384KB of RAM that is never reported when I boot up.

This is normal. Some BIOS versions do not show that area of memory right between conventional memory and extended memory.

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The system is reporting much less memory than is actually in the system.

This is a common question and one with many possible solutions:

* Ensure the memory is fully seated.

* On older EDO systems, a common problem is using a memory module of a size that your motherboard won't support. Most commonly, some boards won't support sizes of 2, 8, or 32 megabytes.

* You need to consult your manual for this info. You may have a memory bank that is not full, and many times in this case the PC will just ignore whatever memory is in that bank. On older 486-class machines using SIMM memory modules, banks comprise of four equally sizes memory modules. The motherboard manual will outline for you which memory slots go to which banks. If these banks are not full or have memory of different sizes in it, it will not work. On Pentium-class machines using 72-pin SIMMs, a bank is two memory slots. More recent systems using DIMMs need not worry about this problem.

* Some motherboards have problems working with composite memory sticks. A composite memory stick is a memory module that is internally wired as if it were really two separate modules working piggy-back. For example, some 32MB modules are wired as two 16MB sticks together. These SIMM modules have chips on both sides of the PCB. As a note, if you run across a 16MB SIMM with chips on both sides of the PCB, beware as this could be a trick module. Most 16MB modules are not composite, but some out there really are.

* Pay attention to the type of memory it is you are using and whether or not your particular chipset supports it.

* If you have a really old system, it may require that you set jumpers when you add memory. It is always a possibility some of your memory is bad.

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My system seems to have slowed down upon adding more memory.

Well, first you need to make sure that all of the new memory is being recognized. Refer to the above question. If your memory upgrade took the system above 64MB of RAM and you have a chipset that doesn't allow cacheing above 64MB (such as the Intel VX, FX, and TX chipsets), then there isn't much you can do. Those chipsets cannot internally cache more than 64MB, so any memory above that mark will just slow down the system. also, check to see if the new memory you added is equivalent or faster than the old stuff. One common mistake is to install memory that is slower than what was already in there. This causes the system to reduce the OVERALL speed down to that of the slower memory. For example, installing -70 ns speed memory is a system that already had -60 ns memory will decrease the speed. [Top] I am getting a memory parity error when I boot up.

* If it crashes as soon as you turn it on, you are probably trying to run non-parity memory in a parity system. Replace it.

* Make sure parity checking wasn't accidentally turned on in BIOS with non-parity memory in the slots.

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I am getting parity errors during normal operation of the PC.

If you just get them every once in a while, i wouldn't fret over it. Sometimes little errors occur in memory. If you seem to be getting these associated with random lockups, I would check the rest of the system because many things could be bad. Sometimes improper cooling, for example, can cause random errors that may look like something else is awry. It is starts to happen a lot and these other things aren't a factor, then you probably need to replace your memory.

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Receive out of memory error with plenty of memory.

May not be enough conventional memory not system memory. The computers memory is broken into different sections. While you may have enough memory which the program requires you may not have enough conventional, upper, high or extended memory. If you are meeting the system requirements of the program you are trying to run try some of the following suggestions to free up memory. If you are running MS-DOS / Windows 3.xx:

* Try loading sections of your autoexec.bat / config.sys into high memory.

* If you are running the program form Windows 3.x run the program from MS-DOS instead.

* If still receiving errors utilize a boot diskette to run the program. If you are running Windows 95 / Windows 98:

* Try loading sections of your autoexec.bat / config.sys into high memory. * Within windows press CTRL + ALT + DEL and end task all items except explorer and systray and then run the program.

* If the program is a MS-DOS program you may be required to run it from MS-DOS.

* Because Windows 95 and 98 handles memory much more efficiently then previous operating systems generally if you are still receiving out of memory errors it may be related to the program you are trying to use attempt to reinstall it if you still receive errors it is recommend you contact the vendor of the program.

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Installed Memory but Win XP Pro won't start now Question:

I added 256mb to a computer with 128mb. The BIOS sees it but when Windows loads I get a blue screen.

Answer:

It is important that any new RAM module(s) be fully compatible with both the motherboard and/or any other RAM module(s) already in the system. Additionally, there are sometimes jumper switches on older motherboards that need to be reset for new RAM configurations. Consult your motherboard's manual or the manufacturer's web site for specific instructions and compatibility requirements. If you do not have your computer's manual and the manufacturer doesn't provide a support web site, you can use Crucial Memory's web site to determine the correct RAM and capacity for your specific make and model computer and/or motherboard.

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Identify a bad memory module

If you turn on your computer and you hear a series of beeps and the system will not boot, this behavior usually indicates a hardware problem. The beeps that you hear are clues to what the problem could be. Below, is a link that will list the different manufactures Motherboards and the beep codes that are assigned them. http://www.5starsupport.com/info/beep_codes.htm The most common problem that I have seen is either a bad memory module or memory that is not seated correctly. The first step is to unseat your memory modules, then reseat them. If this does not correct the problem and the beep code indicates a memory issue, then replacement would be your next step. If you have multiple memory modules, you can isolate which one is causing the trouble by completely removing one from the system. If the system boots fine, then the modules that are installed are good. Repeat this step until the system refuses to boot. Then you will have found the offending module.