Foldit allows you to run as many clients as you want on as many computers as you want. You can also run multiple clients on a single computer. A Foldit client can be "CPU intensive", meaning that it can use 100% of one CPU or processor. Most computers now have more than one processor. This means the ability to run more than one client at full speed. Typical computers might have 2, 4, or 8 processors, and high-end computers have more. See the technobabble section below for more on the terminology. See "how many CPUs?" for tips on determining the number of processors in the Windows environment.