What is a computer DIMM?

Dual-inline-memory-modules, that is, dual-row direct-insertion storage module. This is a new memory strip that appears after the Pentium CPU is launched, and the DIMM provides a 64-bit data channel so it can be used on a single board on the Pentium motherboard. It has 168 pins, so it is called a 168-line memory bar. It's a bit longer than the Simms slot, and it also supports a new 168-line Edo-dram memory. For the time being, the operating voltage of the memory chip for the DIMM is typically 3.3V (except for the 168-line memory chips using the Edoram memory chip), and the working voltages for Simms's memory chips are generally 5V (using Edoram or Fbram memory chips) and they cannot be mixed.

Comparison between DIMMs and Simms

DIMMs (Dual Inline Memory module, dual inline memory modules) are quite similar to Simms (single In-line Memory module, unilateral contact memory module), except that the two ends of the DIMM's Goldfinger are not interoperable like Simms. , each of which transmits signals independently, thus satisfying the need for more data signals to be transmitted. The same interface with the DDR memory also uses the Dimm,sdram interface is slightly different, the SDRAM DIMM is 168Pin DIMM structure, the gold finger each side is 84Pin, the gold finger has two card ports, is used to avoid inserting the slot, the error will insert the memory backwards to cause the burning; DDR The DIMM uses a 184Pin DIMM structure with a 92Pin finger on each side and only one card on the gold finger. The difference between the number of cards is the most obvious distinction between the two. The DDR2 DIMM is a 240pin DIMM structure with a 120Pin on each side of the golden finger and a single card on the finger of the DDR DIMM, but the position of the card is slightly different from the DDR DIMM, so the DDR memory is not plugged into the DDR2 DIMM. Similarly DDR2 memory is not plugged into the DDR DIMM, so there is no problem with the memory plugging slot in some motherboards with both DDR DIMMs and DDR2 DIMMs.

Fb-dimm

Because the current memory is mainly in the traditional 64-bit parallel design, that is, the North Bridge chip memory controller and memory modules are all through the 64-bit parallel bus to exchange data, but this type of parallel bus design has one of the biggest disadvantage: the adjacent circuit is very easy to be disturbed. This is because the current DIMM uses a "Short line Connection" (Stub-bus) topology. In this structure, each chip and memory controller of the data bus has a short line connected, which will cause resistance discontinuity, thus affecting the stability and integrity of the signal, the higher the frequency or chip particles, the impact is greater. This is also the reason for the low frequency of memory such as the DDR currently based on such parallel systems. Small Outline Dual Inline Memory Module (abbreviated SODIMM): Small profile dual-row straight-Plug memory module