Computer performance is generally measured in terms of throughput -- the number of data items a computer can process in a given amount of time. The main factors influencing a computer's performance are the instruction set, algorithms and architecture of the hardware, the operating system, the number and speed of processors, the amount of RAM and disk space, and the speed of the bus connecting the processor to memory and devices. Other factors affecting performance can include scheduling of computing resources, optimization of code, and the use of specialized instructions.