Crucial 4GB (1x4GB) 2133MHz, CL15, Unbuffered, NON-ECC, 1.2V, DDR4. Backed by a Crucial Lifetime warranty. Overcome one of your greatest server limitations: memory. From networking, cloud computing, and virtualization to HPC, Big Data and more, memory-dependent server applications require increasingly higher densities of memory and higher levels of performance than are attainable on current DDR3 technology.