Difference between DDR2 and DIMM.

Modules of RAM on modern computers can be presented in a variety of modifications. Among the most common are DDR2 and DIMM. What are they?

Facts o DDR2

DDR2 is a type of RAM for PCs and computer video cards, which has a main bus that operates at about twice the frequency of the one installed in the previous generation RAM modules - DDR. There are 240 pins in the design of DDR2 RAM chips.

DDR2 modules are available in 5 main modifications, differing in frequency (from 100 MHz, at which the least productive version works, to 266 MHz, which is installed for the fastest types of DDR2 RAM).

DDR2 RAM can be supplemented with:

  • special error correction chips;
  • modules for additional registration of cell addresses;
  • chips for buffering data.

DDR2 modules are characterized by very high bandwidth, low power consumption, efficient design (in terms of cooling system operation). At the same time, in some cases, access to data in DDR2 modules operating at high frequencies can occur with a delay that exceeds that of the previous generation microcircuits.

Facts about DIMMs

DIMMs, in turn, are not a type of RAM, but a form factor of the corresponding modules. That is, in fact - a design concept that manufacturers of RAM chips adhere to in order to achieve mutual compatibility of products. Brands that supply DDR2 memory modules to the market are no exception. The DIMM standard also corresponds to such modifications of RAM chips as DDR3 and DDR4.

DIMMs are rectangular microcircuits with independent pins on either side. In turn, the contacts in the RAM, corresponding to the historically preceding DIMM form factor - SIMM, are interconnected.

DIMMs are ideal for installation in 64-bit computers. Actually, many IT specialists associate the development and distribution of this form factor with the growing popularity of 64-bit PCs. Historically, however, DIMMs have been around for a long time - since the early 90s. Then they were installed on workstations.


The main difference between DDR2 and DIMM is that DDR2 is a technological type of RAM modules, and DIMM is a form factor. At the same time, DDR2 in modern versions in most cases is made in the DIMM standard. In turn, not every DIMM form factor is presented in DDR2 - as we noted above, DIMM modules of RAM have been used since the early 90s, when DDR2 RAM was not even introduced to the market. Perhaps - not even invented.

Having defined what is the difference between DDR2 and DIMM, we note its key criteria in a small table.


What do they have in common?
Most modern DDR2 modules for PCs are made in DIMM form factor
difference between them?
Is a technological type of RAM modules for PCsIs a form factor in which modules are executed for various types of computers - including DDR2
DDR2 modules appeared on the market in the early 2000sDIMM form factor has been used since the early 90s