I just want to share results of some testing which I was conducting upon joining this forum. I came to RT-AC66U H/W ver. A1 after using TP-Link TL-WL1043ND and TL-WA901ND in my home network, for 5 years. It was like a coming on a light from a dungeon... I was thrilled and still I'm. I don't have any issue with it and when I saw that some members have different problems, I decided to do some testing. so, here is my setup: PC desktop connected wired to first LAN port of RT-AC66U, which WAN port is furthermore connected wired to Cisco EPC3212 cable modem. I have 40Mbs internet connection. On 2nd and 3rd LAN port I connect Synology DS1511+ NAS which NIC's are configured as Network Fault Tolerance only and finally on 4th LAN port I connected TrendNet TEW-692GR for extend range purposes. I use Sony Vaio laptop with Intel Centrino Ultimate-N 6300 WiFi card for signal measure. Both computers running Windows 8 Enterprise x64. RT-AC66U is placed vertically with vertically placed antennas too. Vaio is placed on 2m distance from router and inSSIDer 126.96.36.1993 is used for measurement. RT-AC66U setup as following: SSID same for both band. (Vaio setup: Prefer 5.2GHz, highest power, medium roaming aggressiveness) 2,4GHz N Only 40MHz b/w contr. ch. 1L WPA2-PSK AES Tx bursting enable WMM APSD enable 125mW 5GHz N Only 80MHz b/w cont.ch. 36 WPA2-PSK AES Tx bursting enable WMM APSD enable 125mW with FW 188.8.131.52.266: 2,4GHz signal, RSSI -15dBm 5GHz signal, RSSI -19dBm laptop WiFi status: speed 300.0Mbps÷360Mbps fluctuated transfer 20GB file from NAS to laptop, getting 26-27MBs with FW 184.108.40.206.270 2,4GHz signal, RSSI -17dBm 5GHz signal, RSSI -34dBm laptop WiFi status: speed 450.0Mbps transfer 20GB file from NAS to laptop, getting 49-52MBs with FW 220.127.116.11.321 2,4GHz signal, RSSi -17dBm 5GHz signal, RSSI -35dBm÷-37dBm fluctuated laptop WiFi status: speed 450.0Mbps transfer 20GB file from NAS to laptop, getting 43-45MBs with FW 18.104.22.168.270.24 beta3 2,4GHz signal, RSSi -17dBm 5GHz signal, RSSI -31dBm÷-34dBm fluctuated laptop WiFi status: speed 450.0Mbps transfer 20GB file from NAS to laptop, getting 43-45MBs temperature 2,4GHz 58°C, 5GHz 64°C.