Switches can be designed to forward frames in one of two ways: store and forward, or cut-through
STORE AND FORWARD
A switch performing store-and-forward will wait to forward a frame until it has received the entire frame. Store-and-forward is most often used in environments supporting reliable physical or datalink protocols. A received frame is often checked for errors before being forwarded. This type of switch is inherently slower in environments where upper layer protocols already provide reliable services. The tipoff that you are dealing with a store and forward style switch is whether the switch has buffers.
CUT THROUGH
Cut-through switches begin forwarding the frame as soon as the switch has read the destination address. A cut through switch will forward the data before it has completed receiving the frame. These switches will function at wire speed, forwarding traffic as fast as it receives it. Nearly all cut-through switches have no RAM buffers for storing frames.