Minimum System Requirements for PC Operating system: Windows 98, 98SE, ME, 2000 and XP. CPU: 450 MHz Pentium III or faster processor Graphics card: 16 MB graphics card (DirectX 8.0 or higher compatible) RAM: 128 MB Hard Disk Space: 100 MB Minimum System Requirements for Mac Operating system: OS X 10.3.9 or 10.4.6 CPU: G4 or faster processor Graphics card: NVidia GeForce 5200/ATI Radeon 7500 or better RAM: 256 MB Hard Disk Space: 100 MB http://cache.lego.com/downloads/ldd/install/pc/1_6_680/designer. exe