The physical memory, also known as RAM (random access memory) is one of the most important components of a computer system, as it stores data for running application, as well as transitional data from one component to the other ( for instance, some data ca travel from the GPU to the CPU through RAM). RAM errors may be caused by several factors. Improper configuration is BIOS is probably the most common source of RAM errors. A bugged BIOS or operating system can also be a cause, as well as physical flaws in the chips themselves.
If you experience one of the following symptoms, you should consider checking your RAM for errors.
• Blue screens of death
• Black screens
• Unexpected system restarts
• Unexpected system shut downs
• Slow computer and/or system start up.
• Weird sounds coming from the computer case
Windows Vista and Windows Seven have an built-in memory diagnostic tool. From my own experience, I can tell you; this tool is not very reliable. It is mostly tuned to find physical flaws in memory chips, and very rarely manages to detect logical flaws (improper configuration or poor BIOS management). To use this tool, press the start button (or strike the windows key), in the “search programs and files” write “memory diagnostic tool”; the first result that search returns is the windows memory diagnostic tool. The memory can’t be properly tested while the system is running; therefore you must schedule the test for the next restart. This diagnostic tool contains several tests, but it is not very accurate.
We must resort to some third party specialized tests, such as memtest86, for more accurate results. Memtest86 comes in two versions. One that is bootable, and runs before system start up, and one that runs in parallel with the system. The latter version is not very accurate, as it can only test blocks of memory which are not used by any application. The first version (bootable image) is the one you should be using if you want an accurate testing of the memory. It contains 9 tests, divided into three big groups. The first 4 tests will look for physical flaws in the chips. Tests 5 through 7 will look for logical flaws in the memory configuration. Tests 8 and 9, which can take a day or two to complete, depending on the amount of RAM, check for stress weaknesses as well as physical and logical flaws. The last two tests usually find errors that the first tests would have discovered anyway, so it is not mandatory to run them.
Once an error is found, the test stops. It is enough to have one error for your memory to not work properly and pose a threat to the entire system. Depending on the test that found the error, there are different ways of fixing the error. Note that if you use several memory chips, it is impossible for the test to tell in which chip the error was found. Therefore, it is a good idea to test each chip independently and then in combinations, till you tested every possible configuration.
Regardless of which test found the error, there is basic troubleshooting that should be done.
First, you should update your BIOS. I know that sounds very dangerous, but BIOS can easily be updated through automated applications that run in a windows environment. These applications can be found on the website of the motherboard manufacturer, or on the CD that came with your motherboard.
After the BIOS is updated, you need to enter the BIOS setup and manually set the RAM timings, frequency and voltage to their appropriate values. You find these values on the chip’s manufacturer website or on the documentation that came with the chips. Once you done these two steps, run the test again. If errors are still found, regardless of test, you need to replace the chips.