I've been twiddling my Access Point (AP) settings and discovered that disabling CTS protection mode significantly increases Wifi throughput in a low transmission error network. CTS (Clear-To-Send) protection mode should be enabled when your Wireless-G devices are experiencing problems, for example, not being able to transmit to the Router in an environment with heavy 802.11b traffic.
The theory is as follows: When there are many devices connected to an AP they can sometimes transmit to the AP at the same time. This can occur when a client cannot detect the other client to determine if it is transmitting on the same channel. In the case of this collision, the AP discards the colliding data and the error rate is increased.
CTS protection helps by choosing which device gets to transmit at each moment. The client has to send a request to send (RTS) to the AP. The AP then replies with a CTS packet and then only listens to that client until the client has completed transmitting. This overhead decreases throughput.
Most APs also allow one to change the RTS threshold. This specifies the packet size requiring an RTS. On a very noisy network where there are a lot of transmission errors one can bring the RTS threshold right down making clients send RTS packets for smaller packet.s, but this will decrease performance.
With CTS enabled it should help 802.11B/G devices to have a chance to transmit to the AP. If your network error rate is low, disable CTS protection to get better performance.
Hope that helps!