The RAM from PHS-memory is specifically designed for the Sony VAIO VGN-Z31WN model and offers a storage capacity of 4 gigabytes. With a memory clock frequency of 1066 megahertz (MHz), this DDR3 RAM ensures reliable and efficient performance. The SO-DIMM form factor is ideal for laptops and allows for easy installation. The memory operates at a voltage of 1.5 volts and features 204 pins, making it an optimal choice for upgrading or replacing the existing memory in compatible devices. The 100% compatibility with the Sony VAIO VGN-Z31WN ensures that users can benefit from improved system performance and smooth usage. This RAM is a sensible investment for anyone looking to enhance their laptop's performance.