ECC RAM stands for Error Checking and Correction Random Access Memory. As the short form indicates, ECC Memory is one of the types of RAM. With the use of ECC RAM, this allows the system to trace and correct single bit errors. The drawback, thought, of this memory is that it cannot accurate multiple bit errors, that is why ECC Memory is not generally suggested for personal computers user because they shut down system daily and some time not utilized PC for long time. Also, most modern PCs do not carry ECC at all. ECC Memories mainly used for servers because servers are not shut down.

There are 2 kinds of Memory Errors that an ECC may check and accurate. The Memory Errors are both hard and soft. Hard errors are caused by the defects in manufacture in the memory chip and once they start appearing they cannot be corrected. While Soft errors in contrast, are caused mainly by electrical disturbances. ECC detects and corrects errors depending on the type of error that arises.

ECC Memory is also of 2 types. It is both buffered and unbuffered, if your ECC is buffered, it can hold data for the moment for one whole clock cycle before it is transported. This, though, foregoes speed because of the extra clock cycle.
Alternatively, if your ECU is unbuffered, the machine is allowed directly to access every memory chip on the module. This, however, foregoes a little bit of its consistency in spite of its being faster that the registered or buffered ECC.

Most users rather select non- ECC Memory or unbuffered ECC than ECC Memory or buffered ECC possibly for the following reasons:

1. ECC Memory is expensive than the non- ECC Memory;

2. The motherboard that supports ECC functionality in RAM is also costly; and possibly

3. ECC Memory controllers need extra time to check and correct the error.