I've installed the firmware tomato-K26USB-1.28.RT-N5x-MIPSR2-132-AIO-64K on my RT-N66U router. Everything mostly works great.
However, when I enable QoS, my download speed is limited to approximately 64Mbps. My cable internet bandwidth plan is 150Mbps down/12Mbps up. As soon as I enable QoS, my download speed drops to ~64Mbps but when I disable it returns to normal, usually around 135Mbps. I'm not using PPPoE and the CPU is not working very hard during my speed test.
Any help would be appreciated.