Computers and motherboards are designed to use a particular memory type. Your machine will not boot if the incorrect memory type is installed. Memory density is one of the factors that can affect whether the memory will work in your machine. (For more info on memory types see our article 'RAM Types Explained'.)
The terms high density and low density refer to the way the DRAM chips are organized on the memory module.
As an example, a typical dual channel low density non-ECC unbuffered 512MB memory module would be organized as 2 banks of 32 x 8 (32 Mbits and a data width of 8 bits). A high density 512MB module (usually ECC Registered server memory) would typically be 64 x 4 (64 Mbits and a data width of 4 bits). If the divisor is x8 the memory is low density. If the divisor is x4 the memory is high density.
DDR2 and later memory modules usually include density information on the label. 1Rx8 or 2Rx8 are low density, 1Rx4 or 2Rx4 are high density (usually server RAM).
There is no high density Non-ECC unbuffered desktop RAM produced by major memory manufacturers because it does not comply with JEDEC standards. If you need memory for a desktop PC that requires non-ECC unbuffered memory type, buy major brand Non-ECC unbuffered memory. You generally will not need to worry about accidentally buying high density RAM if you choose the correct memory type from a major manufacturer.
A few sellers on eBay carry off brand non-ECC memory which is high density. This memory only works with a very small number of motherboards and is not compatible with any Intel motherboards that require non-ECC memory. Read item descriptions carefully prior to purchase.
ECC registered server RAM and ECC unbuffered workstation RAM are not compatible with desktop PCs that require Non-ECC unbuffered RAM. See our article on memory types for more info.
© 2016 GeeK NoiZe®. All Rights Reserved