UCSF Chimera and ChimeraX downloads are available for current versions of the Windows and macOS operating systems and some Linux distributions. Versions of these operating systems that are past end-of-life such as Windows 7 are not supported, and neither are old versions of these operating systems (even if not yet end-of-life) when required libraries (e.g., the Qt window toolkit used by ChimeraX) are no longer available. See the download pages of the respective programs [Chimera] [ChimeraX] for currently supported operating system versions.

Chimera and ChimeraX are real-time interactive 3D graphics applications. The required level of graphics processor (GPU) performance depends on the intended use. For uses with data of modest size (structures < 50,000 atoms, map size < 256x256x256), any recent computer graphics hardware will suffice. A mid-level GPU is recommended for working with very large datasets, and a higher-end GPU recommended for more demanding situations such as using ChimeraX with ISOLDE for interactive dynamics with flexible fitting, or with virtual reality headsets.

We provide support only for uses where the application, the graphics rendering, and the display are on a single desktop or laptop computer. Technologies that run the application on one computer or a cluster, but that display or compute graphics on a different computer are not supported. Examples of unsupported configurations include X11 remote display, VirtualGL, Microsoft Remote Desktop, and VNC. While users have successfully configured some of these unsupported distributed computing technologies, ChimeraX makes extensive use of 3D OpenGL graphics rendering, which can be difficult to configure and often provides unreliable or slow interactive performance when the rendering or display is not on the same computer that is running the application. Even if a user has the technical expertise to set up one of these unsupported configurations, we recommend against it because of the poor interactive performance. We also do not support running Chimera or ChimeraX on a virtual machine, as configuring graphics drivers to use GPU acceleration on a virtual machine presents technical issues. The ChimeraX development team does not have the computer systems on which to test these unsupported configurations.