3x470 4gb(1100/1850), windows 8.1 crimson 16.9.1 almoust stock.
In 1 hour frozen 2 times, only reboot helps.

20:13:10:351   bec   GPU0 t=32C fan=31%, GPU1 t=48C fan=35%, GPU2 t=45C fan=32%
20:13:10:351   bec   em hbt: 0, fm hbt: 63,
20:13:10:351   bec   watchdog - thread 0, hb time 63
20:13:10:351   bec   watchdog - thread 1, hb time 16
20:13:10:351   bec   watchdog - thread 2, hb time 16
20:13:10:351   bec   watchdog - thread 3, hb time 63
20:13:10:352   bec   watchdog - thread 4, hb time 86578
20:13:10:352   bec   WATCHDOG: GPU 2 hangs in OpenCL call, exit
20:13:10:352   bec   watchdog - thread 5, hb time 86531
20:13:10:352   bec   WATCHDOG: GPU 2 hangs in OpenCL call, exit
20:13:11:369   bec   Restarting OK, exit...