Nvidia 1070 can't be surported in Daz Studio's Iray render

My graphcard is nvidia 1070,8GB graphram.

In Daz Studio public build 4.9.3.71,Iray Render can't use GPU, the graph card is in render setting hardware list,but when checked this grapg card,render will quit.

the log:

2016-09-04 00:15:31.597 WARNING: dzneuraymgr.cpp(261): Iray ERROR - module:category(IRAY:RENDER):   1.0   IRAY   rend error: Cannot render: found no usable devices.
2016-09-04 00:15:31.600 Iray Render error: Invalid parameters (NULL pointer).

What's wrong???