Computer Memory FAQ

Can I use faster memory in a slower system?

Yes, a faster memory module should work fine in a system with a lower memory speed rating. For example, PC133 memory should work fine in a system that takes PC100 or PC66.

Can I use DDR memory in a PC using PC133/PC100/PC66 memory?

No, DDR memory has a different specification and will not work in a PC using PC133, PC100, or PC66 memory.

What is the difference between CL=2 and CL=3?

CL stands for CAS Latency. The number represents an initial delay in clock cycles before a requested stream of data is available. Therefore, CL=2 will be slightly faster than CL=3.

Why am I getting an out of memory error with my Windows 95/98/Me system when I have plenty of memory installed?

If you have a large amount of memory installed (more than 512MB), you may experience this error. This can be fixed by adding a MaxFileCache value to the [vcache] section of system.ini. See this Microsoft knowledge base article for more details:
KB Article 253912 - "Out of Memory" Error Messages with Large Amounts of RAM Installed

What is the difference between ECC and non-parity memory?

ECC (Error Correction Code) memory will detect and correct any memory errors while the system is running. It is mainly used in server environments where operation is critical. Non-parity memory does not contain any error correcting circuitry. In reality, memory errors are rare so going with non-parity is the best choice for home or office use.

Can I use an ECC memory module in a PC that does not support ECC?

Yes, but the ECC memory module will run in non-ECC mode.

What are the differences among registered, buffered, and unbuffered memory?

Registered memory is designed for motherboards that accept a large number of module slots and larger capacity modules. This type of memory is mainly used in servers that require a large amount of memory. Buffered memory is basically the same as registered memory, but the term is used for the older EDO and FPM memory. Unbuffered memory does not contain the chip that allows the extra memory feature in registered and buffered memory. Unbuffered memory is cheaper and the popular choice in home computers.

Can I use registered memory with unbuffered memory?

No, registered memory will not work with unbuffered memory.

What is dual channel DDR?

Dual channel DDR involves using 2 DDR memory modules to double the memory bandwidth. The DDR memory modules themselves are not any different. The only requirement is that the memory controller on the motherboard support this dual channel interface.

Visit my Memory deals and advice section