I have an RB751U-2HnD setup with multiple SSIDs that lands the user in multiple VLANs depending upon which SSID they connect to. The way that I have found to implement this is to create a bridge between each SSID and each VLAN. I have read that this will be limiting to the throughput because of the load on the CPU however I did not know that it would be as bad as it is. I can only get about 8Mbps of traffic through the device as the CPU reaches 100%. Is this to be expected? If so is there any other way to setup multiple SSIDs and keep the traffic of each in separate networks?

This is how we would setup the same kind of network. How are you doing your speed test?

I'm just looking at the interface statistics while copying a file from a laptop to a server using the bridged SSID-VLAN.