Folding@home is a distributed computing project, currently based at the Washington University in St. Louis School of Medicine, for performing molecular dynamics simulations of protein dynamics. Its initial focus was on protein folding but has shifted to more biomedical problems; such as fighting Alzheimer’s disease, cancer, Coronavirus Disease 2019 (COVID-19), and Ebola. The project uses the idle processing resources of personal computers owned by volunteers who have installed the software on their systems. Folding@home is helping scientists understand the structure of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that causes COVID-19, as a better understanding of the virus could aid in the development of life-saving drugs.

The project uses scientific computer programs, referred to as FahCores, to perform calculations. Folding@home’s cores are based on modified and optimized versions of molecular simulation programs for calculation, including TINKER, GROMACS, AMBER, CPMD, SHARPEN, ProtoMol and Desmond. These variants are each given an arbitrary identifier, i.e. Core xx. While the same core can be used by various versions of the client, separating the core from the client enables the scientific methods to be updated automatically as needed without a client update.

Folding@home uses a client-server architecture. The software first asks the Assignment Server, which acts as a load balancer, for an available and appropriate Work Server. The Work Server then sends back a Work Unit. A FahCore may also be downloaded from a Web Server, depending on the Work Unit. The completed unit is then sent back to the same Work Server, with a designated Collection Server as a backup. Log files and credits are then collected from the Work Servers and passed to the Statistics Server for tabulation and display.

FAHClient is the central piece of software. Web Control and Advanced Control are graphical interfaces on top of it, and they communicate with FAHClient. FAHClient downloads Work Units and needed FahCores from the Folding@Home servers, and uploads completed Work Units when the FahCore finishes its work. In Windows, FAHClient has a notification area/system tray icon. This allows you to run FAHClient behind the scenes in Windows, just like it does in Linux and macOS, yet still give you control over the process without having to run a low-level tool like Task Manager. It has a popup menu which allows you to quickly control folding or shut it down completely.

To contribute, download and run the Folding@Home Installer. The installer includes the Web Control interface software, the FAHClient software, and the FAHViewer software (which allows you to visualize protein folding simulations and monitor the status of the simulation work units as they run on your computer). For new installs, FAHClient will start paused while it waits for you to either tell it to fold anonymously, or configure a name and/or a team and/or passkey before the first Work Unit is downloaded.

As mentioned above, Folding@home has a notification area icon in the bottom panel next to the clock. Its icon is a multi-cored molecule. If you don’t see it, it may be hidden in the icon overflow area. Right-clicking on it shows a menu of further options. By default, the software will continually run in the background. If you want it to only run when you are idle then you can select On Idle from this control. Alternately the folding slots may be Paused and Un-paused later. The menu offers quick access to the same controls as the Folding Power slider shown below in Web Control. From the menu, you can also open Advanced Control, an interface with more advanced controls and options; and the FAHViewer Protein Viewer. Finally, you can shut down, Quit, Folding@home completely.

The Folding@home software is configured, controlled, and monitored through the simple graphical interface named Web Control. This web browser-based application has several features including client monitoring and configuration of all FAH clients. It is the recommended interface for all FAH types (Single core CPU, Multi-core CPU, GPU). The more advanced FAHControl/Advanced Control application is also available as mentioned above.

To make sure you’re helping with COVID-19 research, have “Any disease” selected under the “I support research fighting” dropdown. This is the default option. When it is enabled, Folding@home will prioritize work related to the coronavirus. Work units may not be available immediately, and your client may work on other diseases while waiting for COVID-19 jobs. The Power Slider can be used to control how much system resources Folding@Home uses. Be aware of electricity consumption from running the Folding@home software which may or may not be appropriate depending on your circumstances.

If you want to have a little more control over your setup, you can use the notification area icon to pull up its Advanced Control; which lets you adjust whether you want folding to continue if your system switches to battery power, as well as plenty of other tweaks if you want to get the most out of your home setup. The software was designed to utilize multiple CPU cores with a multi-core CPU slot and a GPU slot for each supported GPU. This configuration uses a lot more resources compared to using just a single CPU core. While CPU and GPU folding is much more scientifically productive compared to their single-core CPU slot counterpart, they should not be run on machines which cannot tolerate heavy use. If FAH is using too many resources, please adjust the slot configurations to suit your computing capabilities.

If you wish to view and track your Folding@home contribution statistics, you have to set your username and passkey. Go to the Change Identity window, by clicking the Change Identity link on the upper left corner of the Web Control. Here you can obtain a passkey and set your identity with a username. A passkey uniquely identifies you as an individual donor and is associated with results that you have completed. You can change your username at any time. However, old work units will remain credited to the old username. You can also participate in a team. There are many teams already folding for the project. To join that team, simply enter their team number into the client setup. Or you can start a new team using the Create a Team page linked from the Folding@Home Statistics page.