ok i should say that this situation suddenly happened without any changes
this is the log that where clamore restart after 12 hours work without any problem

23:51:54:891   1d14   watchdog - thread 0 (gpu0), hb time 219
23:51:54:891   1d14   watchdog - thread 1 (gpu0), hb time 16
23:51:54:891   1d14   watchdog - thread 2 (gpu1), hb time 204
23:51:54:891   1d14   watchdog - thread 3 (gpu1), hb time 407
23:51:54:906   1d14   watchdog - thread 4 (gpu2), hb time 422
23:51:54:906   1d14   watchdog - thread 5 (gpu2), hb time 219
23:51:54:906   1d14   watchdog - thread 6 (gpu3), hb time 219
23:51:54:906   1d14   watchdog - thread 7 (gpu3), hb time 0
23:51:54:922   1d14   watchdog - thread 8 (gpu4), hb time 16
23:51:54:922   1d14   watchdog - thread 9 (gpu4), hb time 235
23:51:54:922   1d14   watchdog - thread 10 (gpu5), hb time 89735
23:51:54:938   1d14   WATCHDOG: GPU 5 hangs in OpenCL call, exit
23:51:54:938   1d14   watchdog - thread 11 (gpu5), hb time 89968
23:51:54:938   1d14   WATCHDOG: GPU 5 hangs in OpenCL call, exit
23:51:54:938   1d14   watchdog - thread 12 (gpu6), hb time 0
23:51:54:953   1d14   watchdog - thread 13 (gpu6), hb time 234
23:52:02:204   1d14   Restarting OK, exit...


-----------------------------------------------
after restart a lots of log file created like this

23:52:05:017   590   
23:52:05:017   590   ةحححححححححححححححححححححححححححححححححححححححححححححححححححححححححححححححح»
23:52:05:033   590   ؛                Claymore's Dual GPU Miner - v11.9               ؛
23:52:05:033   590   ؛              ETH + DCR/SIA/LBC/PASC/BLAKE2S/KECCAK             ؛
23:52:05:033   590   بحححححححححححححححححححححححححححححححححححححححححححححححححححححححححححححححح¼
23:52:05:033   590   
23:52:05:033   590   b597
23:52:05:251   590   ETH: 1 pool is specified
23:52:05:251   590   Main Ethereum pool is eu1.ethermine.org:4444
23:52:05:251   590   DCR: 0 pool is specified
23:52:38:083   185c   
23:53:10:899   185c   
23:53:43:715   185c   
23:54:16:531   185c   
23:54:49:347   185c   
23:55:22:163   185c   
23:55:54:979   185c   
23:56:27:795   185c   
23:57:00:611   185c   
23:57:33:427   185c   
23:57:33:427   185c   Minimal speed ("-minspeed" option) was set to 175 MH/s. Miner cannot reach this speed for 5 minutes, need to restart miner!
23:57:34:677   185c   Restarting OK, exit...

this occure  whit two gpu's "3,5" rarely gpu 0

iuse claymore 11.9 with 18.5 amd driver. now actually i use claymore 11.5 with  blockchain  driver  before, but this happens  again .with one difference .its not restart claymore but stuck on this :
                            WATCHDOG: GPU 5 hangs in OpenCL call, exit