When the router operates at 600 kb/s + reset, it should be the WAN setting, do you use auto/10/100/1000 Mbps or 100/1000 Mbps? You can set the manual uplink speed higher than your ISP speed. Like I have 15/5 Mbps, I set the uplink at 5500kbps. I set my RTS/Fragmentation Threshold at 30000. These can boost up the data transfer speed. These settings are wired and wireless for WAN upload/download speed.