Patriot Memory's Signature Line DDR2 Non-ECC Unbuffered memory delivers quality, reliability and performance expected for today's computer needs. This 4GB kit (2 x 2GB modules) is designed to run at PC2-6400 (800MHz) at CAS 6 latency timings. Built using specific build-of-materials (BOMs) we ensure that every module meets and exceeds industry standards: offering you a hassle-free upgrade. We certify every component that goes into our modules, including the modules themselves, which must pass strict standards to ensure compatibility, quality and reliability. With free customer service and a lifetime warranty, Patriot Memory's Signature memory modules are a perfect system upgrade option.