Some new benchmarks on ccminer x64 v2.2.4 .
GPU 0+1 -> power 90, core +200, mem +400, i 21
GPU 2+3 -> power 120, core +150, mem +150, i 21
[2018-02-13 12:41:49] GPU #1: Zotac GTX 1080 Ti, 45.03 MH/s
[2018-02-13 12:41:55] GPU #3: GeForce GTX 1080 Ti, 47.25 MH/s
[2018-02-13 12:41:55] accepted: 814/818 (diff 2.398), 178.81 MH/s yes!
[2018-02-13 12:42:21] GPU #2: GeForce GTX 1080 Ti, 46.99 MH/s
[2018-02-13 12:42:22] accepted: 815/819 (diff 2.077), 179.00 MH/s yes!
[2018-02-13 12:42:26] GPU #3: GeForce GTX 1080 Ti, 46.96 MH/s
[2018-02-13 12:42:26] GPU #0: MSI GTX 1080 Ti, 46.19 MH/s
[2018-02-13 12:42:27] GPU #1: Zotac GTX 1080 Ti, 44.98 MH/s
[2018-02-13 12:42:41] GPU #3: GeForce GTX 1080 Ti, 47.05 MH/s
[2018-02-13 12:42:41] accepted: 816/820 (diff 3.089), 179.19 MH/s yes!
[2018-02-13 12:42:45] GPU #2: GeForce GTX 1080 Ti, 47.49 MH/s
[2018-02-13 12:42:49] GPU #0: MSI GTX 1080 Ti, 46.26 MH/s
[2018-02-13 12:42:50] GPU #3: GeForce GTX 1080 Ti, 46.94 MH/s
[2018-02-13 12:42:50] accepted: 817/821 (diff 8.779), 179.36 MH/s yes!
[2018-02-13 12:42:51] GPU #1: Zotac GTX 1080 Ti, 44.88 MH/s
[2018-02-13 12:42:59] GPU #1: Zotac GTX 1080 Ti, 44.87 MH/s
[2018-02-13 12:42:59] accepted: 818/822 (diff 0.984), 179.61 MH/s yes!
[2018-02-13 12:43:29] GPU #2: GeForce GTX 1080 Ti, 45.82 MH/s
[2018-02-13 12:43:30] GPU #0: MSI GTX 1080 Ti, 45.15 MH/s
[2018-02-13 12:43:30] GPU #0: 1832 MHz 215.52 kH/W 209W 61C FAN 85%
[2018-02-13 12:43:30] GPU #3: GeForce GTX 1080 Ti, 44.78 MH/s
[2018-02-13 12:43:31] GPU #1: Zotac GTX 1080 Ti, 43.67 MH/s
[2018-02-13 12:43:38] GPU #0: MSI GTX 1080 Ti, 46.16 MH/s
[2018-02-13 12:43:39] accepted: 819/823 (diff 0.678), 180.07 MH/s yes!
[2018-02-13 12:43:52] GPU #0: MSI GTX 1080 Ti, 45.98 MH/s
[2018-02-13 12:43:52] GPU #1: Zotac GTX 1080 Ti, 45.20 MH/s
[2018-02-13 12:43:53] GPU #1: 1780 MHz 208.80 kH/W 210W 56C FAN 71%
[2018-02-13 12:43:53] GPU #3: GeForce GTX 1080 Ti, 47.28 MH/s
[2018-02-13 12:43:53] GPU #2: GeForce GTX 1080 Ti, 46.39 MH/s
[2018-02-13 12:44:00] accepted: 820/824 (diff 0.983), 180.32 MH/s yes!
[2018-02-13 12:44:00] accepted: 821/825 (diff 0.614), 180.32 MH/s yes!
[2018-02-13 12:44:07] GPU #0: MSI GTX 1080 Ti, 45.87 MH/s
[2018-02-13 12:44:07] accepted: 822/826 (diff 1.314), 180.32 MH/s yes!