i just had
CUDA error 4 - cannot write buffer for DAG
11:53:20:698 18b0 GPU 4, GpuMiner cu_k1 failed 4, unspecified launch failure
11:53:20:698 18b0 GPU 4, GpuMiner kx failed 1
11:53:20:698 1ee8 sent: 225
11:53:20:714 10c4 GPU 0, GpuMiner cu_k1 failed 4, unspecified launch failure
11:53:20:729 b74 GPU 5, GpuMiner cu_k1 failed 4, unspecified launch failure
11:53:20:729 b74 GPU 5, GpuMiner kx failed 1
11:53:20:745 b74 Set global fail flag, failed GPU5
11:53:20:745 ed4 GPU 3, GpuMiner cu_k1 failed 4, unspecified launch failure
11:53:20:760 ed4 GPU 3, GpuMiner kx failed 1
11:53:20:776 10c4 GPU 0, GpuMiner kx failed 1
11:53:20:807 13ec GPU 1, GpuMiner cu_k1 failed 4, unspecified launch failure
11:53:20:807 1de0 GPU 2, GpuMiner cu_k1 failed 4, unspecified launch failure
11:53:20:839 b74 GPU 5 failed
11:53:20:854 efc GPU 5, GpuMiner cu_k1 failed 4, unspecified launch failure
11:53:20:854 efc GPU 5, GpuMiner kx failed 1
11:53:20:854 efc Set global fail flag, failed GPU5
11:53:20:854 efc GPU 5 failed
11:53:20:854 13ec GPU 1, GpuMiner kx failed 1
11:53:20:854 13ec Set global fail flag, failed GPU1
11:53:20:854 13ec GPU 1 failed
11:53:20:760 ed4 Set global fail flag, failed GPU3
11:53:20:854 ed4 GPU 3 failed
11:53:20:854 1de0 GPU 2, GpuMiner kx failed 1
11:53:20:854 1de0 Set global fail flag, failed GPU2
11:53:20:854 1de0 GPU 2 failed
11:53:20:807 10c4 Set global fail flag, failed GPU0
11:53:20:885 10c4 GPU 0 failed
11:53:20:885 5a8 GPU 0, GpuMiner cu_k1 failed 4, unspecified launch failure
11:53:20:885 1394 GPU 2, GpuMiner cu_k1 failed 4, unspecified launch failure
11:53:20:901 1cd0 GPU 1, GpuMiner cu_k1 failed 4, unspecified launch failure
11:53:20:901 1cd0 GPU 1, GpuMiner kx failed 1
11:53:20:901 59c GPU 3, GpuMiner cu_k1 failed 4, unspecified launch failure
11:53:20:901 5a8 GPU 0, GpuMiner kx failed 1
11:53:20:901 1394 GPU 2, GpuMiner kx failed 1
11:53:20:698 18b0 Set global fail flag, failed GPU4
11:53:20:901 1cd0 Set global fail flag, failed GPU1
11:53:20:901 59c GPU 3, GpuMiner kx failed 1
11:53:20:901 5a8 Set global fail flag, failed GPU0
11:53:20:901 1394 Set global fail flag, failed GPU2
11:53:20:901 13b8 GPU 4, GpuMiner cu_k1 failed 4, unspecified launch failure
11:53:20:901 18b0 GPU 4 failed
11:53:20:901 1cd0 GPU 1 failed
11:53:20:901 59c Set global fail flag, failed GPU3
11:53:20:917 5a8 GPU 0 failed
11:53:20:917 1394 GPU 2 failed
11:53:20:917 13b8 GPU 4, GpuMiner kx failed 1
11:53:20:917 59c GPU 3 failed
11:53:20:917 13b8 Set global fail flag, failed GPU4
11:53:20:917 13b8 GPU 4 failed
11:53:25:448 12d8 srv_thr cnt: 1, IP: 192.168.1.68
11:53:25:448 12d8 recv: 51
11:53:25:448 12d8 srv pck: 50
11:53:25:464 12d8 srv bs: 0
11:53:25:464 12d8 sent: 196
11:53:26:605 1548 buf: {"id":0,"jsonrpc":"2.0","result":["0x377e4d3a4c19416e09053a0dbf13301255827e3b9315086f09e2c21132c6198b","0x32a2478e57a4b36e5f5e5420e5443a5a82dac6ff01a0548737fada91d743d7d0","0x0112e0be826d694b2e62d01511f12a6061fbaec8bc02357593e70e52ba","0x4fb71a"]}
11:53:26:605 1548 ETH: 03/09/18-11:53:26 - New job from eu1.ethermine.org:5555
11:53:26:605 1548 target: 0x0000000112e0be82 (diff: 4000MH), epoch 174(2.36GB)
11:53:26:605 1548 ETH - Total Speed: 0.000 Mh/s, Total Shares: 1969, Rejected: 1, Time: 11:55
11:53:26:605 1548 ETH: GPU0 0.000 Mh/s, GPU1 0.000 Mh/s, GPU2 0.000 Mh/s, GPU3 0.000 Mh/s, GPU4 0.000 Mh/s, GPU5 0.000 Mh/s
11:53:27:777 1548 ETH: checking pool connection...
11:53:27:777 1548 sent: {"worker": "", "jsonrpc": "2.0", "params": [], "id": 3, "method": "eth_getWork"}
11:53:27:824 1548 buf: {"id":3,"jsonrpc":"2.0","result":["0x377e4d3a4c19416e09053a0dbf13301255827e3b9315086f09e2c21132c6198b","0x32a2478e57a4b36e5f5e5420e5443a5a82dac6ff01a0548737fada91d743d7d0","0x0112e0be826d694b2e62d01511f12a6061fbaec8bc02357593e70e52ba","0x4fb71a"]}
11:53:30:449 1830 srv_thr cnt: 1, IP: 192.168.1.68
11:53:30:449 1830 recv: 51
11:53:30:449 1830 srv pck: 50
11:53:30:465 1830 srv bs: 0
11:53:30:465 1830 sent: 196
11:53:31:824 4d8 em hbt: 15, fm hbt: 15,
11:53:31:824 4d8 watchdog - thread 0 (gpu0), hb time 11312
11:53:31:824 4d8 watchdog - thread 1 (gpu0), hb time 11125
11:53:31:824 4d8 watchdog - thread 2 (gpu1), hb time 11187
11:53:31:824 4d8 watchdog - thread 3 (gpu1), hb time 11312
11:53:31:824 4d8 watchdog - thread 4 (gpu2), hb time 11297
11:53:31:840 4d8 watchdog - thread 5 (gpu2), hb time 11188
11:53:31:840 4d8 watchdog - thread 6 (gpu3), hb time 11188
11:53:31:840 4d8 watchdog - thread 7 (gpu3), hb time 11313
11:53:31:840 4d8 watchdog - thread 8 (gpu4), hb time 13906
11:53:31:840 4d8 watchdog - thread 9 (gpu4), hb time 11172
11:53:31:840 4d8 watchdog - thread 10 (gpu5), hb time 11266
11:53:31:840 4d8 watchdog - thread 11 (gpu5), hb time 11406
11:53:31:855 4d8 WATCHDOG: GPU error, you need to restart miner :(
11:53:33:081 4d8 Restarting OK, exit...
this happened after 12h .. using same OC settings, i was able to run phoenix miner for 48h w/o a single error.
i messed with the "-eres" option, raised the value. hope it helps.