I never get 100W.
Always about 120W per Card. (MSI GeForce GTX 1070 ARMOR 8G OC with Micron Memory)

Wattmeter says 470W from the wall.  
Only 1 ssd connected, nothing else

Setting:
60% tdp
200 coreclock
0 memory

Temp: GPU0: 56C GPU1: 58C GPU2: 48C
GPU0: 419 Sol/s GPU1: 431 Sol/s GPU2: 422 Sol/s
Total speed: 1272 Sol/s
+-----+-------------+--------------+
| GPU | Power usage |  Effecincy   |
+-----+-------------+--------------+
|  0  |    116W     |  3.61 Sol/W  |
|  1  |    119W     |  3.62 Sol/W  |
|  2  |    120W     |  3.52 Sol/W  |


And very often "Connection to GPU1 lost"