Product Detail Run more tasks, processes, and applications simultaneously with 2.53 GHz Intel Xeon Quad-Core E5540 processor See, share, and show your work across the world with built-in HP SkyRoom collaboration solution Tool-less chassis and uncluttered internal design simplify access and service for adding or changing components 500 GB hard drive, 3 GB of RAM, 16x LightScribe DVD drive Pre-installed with Windows Vista Business OS with downgrade to Windows XP Professional . The "HP Z600 Workstation Computer - E5540 2.53GHz 3GB RAM" is best product for you. We recommended HP Z600 Workstation Computer - E5540 2.53GHz 3GB RAM