The Dell YWJTR 4GB 1RX8 PC3L-12800E DDR3-1600 ECC Unbuffered Server Memory is a UDIMM. An unbuffered, low density, low-latency DIMM that doesn't include a register or buffer chip. UDIMMs are generally used in applications requiring the lowest possible latency. Random-access memory (RAM) is the workhorse behind the performance of your system. RAM temporarily stores information from your operating system, applications, and data in current use. This gives your processor easy access to the critical information that makes your programs run. The amount of RAM you have and the memory architecture of your system helps determine how many programs can be executed at one time, how much data can be readily available to a program and helps determine how quickly your applications perform and how many applications you can easily toggle between at one time.
Substitute PN:
 HMT451U7AFR8A-PB