Try routing? The following is a ping test to a RB532 w/ an SR2 card. However I am the sole wireless client on the network.
C:\Documents and Settings\Administrator>ping 10.100.1.1 -t
Pinging 10.100.1.1 with 32 bytes of data:
Reply from 10.100.1.1: bytes=32 time=3ms TTL=64
Reply from 10.100.1.1: bytes=32 time=2ms TTL=64
Reply from 10.100.1.1: bytes=32 time=2ms TTL=64
Reply from 10.100.1.1: bytes=32 time=2ms TTL=64
Reply from 10.100.1.1: bytes=32 time=2ms TTL=64
Reply from 10.100.1.1: bytes=32 time=6ms TTL=64
Reply from 10.100.1.1: bytes=32 time=2ms TTL=64
Reply from 10.100.1.1: bytes=32 time=2ms TTL=64
Reply from 10.100.1.1: bytes=32 time=2ms TTL=64
Reply from 10.100.1.1: bytes=32 time=2ms TTL=64
Reply from 10.100.1.1: bytes=32 time=3ms TTL=6
Reply from 10.100.1.1: bytes=32 time=2ms TTL=64
Reply from 10.100.1.1: bytes=32 time=12ms TTL=64
Reply from 10.100.1.1: bytes=32 time=2ms TTL=64
Reply from 10.100.1.1: bytes=32 time=5ms TTL=64
Reply from 10.100.1.1: bytes=32 time=3ms TTL=64
Reply from 10.100.1.1: bytes=32 time=2ms TTL=64
Reply from 10.100.1.1: bytes=32 time=2ms TTL=64
Reply from 10.100.1.1: bytes=32 time=2ms TTL=64
Reply from 10.100.1.1: bytes=32 time=2ms TTL=64
Reply from 10.100.1.1: bytes=32 time=4ms TTL=64
Reply from 10.100.1.1: bytes=32 time=2ms TTL=64
Reply from 10.100.1.1: bytes=32 time=2ms TTL=64
Reply from 10.100.1.1: bytes=32 time=2ms TTL=64
Reply from 10.100.1.1: bytes=32 time=2ms TTL=64
Reply from 10.100.1.1: bytes=32 time=4ms TTL=64
Reply from 10.100.1.1: bytes=32 time=2ms TTL=64
Reply from 10.100.1.1: bytes=32 time=6ms TTL=64
Reply from 10.100.1.1: bytes=32 time=2ms TTL=64
Reply from 10.100.1.1: bytes=32 time=3ms TTL=64
Reply from 10.100.1.1: bytes=32 time=4ms TTL=64
Reply from 10.100.1.1: bytes=32 time=3ms TTL=64
Reply from 10.100.1.1: bytes=32 time=4ms TTL=64
Reply from 10.100.1.1: bytes=32 time=3ms TTL=64
Reply from 10.100.1.1: bytes=32 time=5ms TTL=64
Reply from 10.100.1.1: bytes=32 time=5ms TTL=64
Reply from 10.100.1.1: bytes=32 time=3ms TTL=64
Reply from 10.100.1.1: bytes=32 time=6ms TTL=64
Reply from 10.100.1.1: bytes=32 time=4ms TTL=64
Reply from 10.100.1.1: bytes=32 time=4ms TTL=64
Reply from 10.100.1.1: bytes=32 time=5ms TTL=64
Reply from 10.100.1.1: bytes=32 time=2ms TTL=64
Reply from 10.100.1.1: bytes=32 time=2ms TTL=64
Reply from 10.100.1.1: bytes=32 time=2ms TTL=64
Reply from 10.100.1.1: bytes=32 time=2ms TTL=64
Reply from 10.100.1.1: bytes=32 time=3ms TTL=64
Reply from 10.100.1.1: bytes=32 time=2ms TTL=64
Reply from 10.100.1.1: bytes=32 time=2ms TTL=64
Reply from 10.100.1.1: bytes=32 time=2ms TTL=64
Reply from 10.100.1.1: bytes=32 time=2ms TTL=64
Reply from 10.100.1.1: bytes=32 time=2ms TTL=64
Reply from 10.100.1.1: bytes=32 time=3ms TTL=64
Reply from 10.100.1.1: bytes=32 time=2ms TTL=64
Reply from 10.100.1.1: bytes=32 time=2ms TTL=64
Reply from 10.100.1.1: bytes=32 time=2ms TTL=64
Reply from 10.100.1.1: bytes=32 time=2ms TTL=64
Ping statistics for 10.100.1.1:
Packets: Sent = 56, Received = 56, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 2ms, Maximum = 12ms, Average = 2ms
Also Yappa,
3Mb is your backhaul? or does each individual user have a 3Mbps queue? 802.11b w/ a connection @ 11mbps has a total throughput of 5.5-6mbps. There are other factors that can effect latency... How is the rest of the network designed is it a Flat topology, bridged? If so depending on the amount of users you have on your network broadcast traffic will kill your ping times especially when going through a half duplex wireless AP. You only want legitimate traffic destined for users on that subnet traversing your wireless AP.
Also 802.11 uses CSMA/CA so the more users you put on a wireless segment the more likely there are going to be collisions leading to retransmissions and back off algorithms, causing increased latency, or spikes.
Another thing to look into, check the p/s (packets per second) on the wireless AP when utilization is low.. That will give you an idea of how much broadcast traffic is being sent over the network, on bridged networks I've seen with 200+ users there was a consistant 130-200p/s going through the network, even when no substantial data was being transmitted/recieved.
This is where bridging negatively effects wireless performance.
Just some things to think about...