I have the problem that Knime doesn't use my GPU in the DL4J nodes. I have check the box that says that DL4J should use the GPU and restart Knime, the box is unselected afterwards.
The log file then says:
2017-11-01 18:22:09,184 : INFO : Worker-1 : DL4JPluginActivator : : : CPU backend will be used.
2017-11-01 18:22:09,184 : DEBUG : Worker-1 : DL4JPluginActivator : : : org.knime.ext.dl4j.bin.windows.x86_64.cpu_0.8.0.v201703291351 matches org\.knime\.ext\.dl4j\.bin\.[^\.]+\.x86_64\.cpu.*
2017-11-01 18:22:09,184 : DEBUG : Worker-1 : DL4JPluginActivator : : : The following backend fragment will be used: org.knime.ext.dl4j.bin.windows.x86_64.cpu_0.8.0.v201703291351
I have a Geforce GTX 1080 from ASUS and Cuda v8.0.44 installed.
There seems to be a little bug in the preference page. Could you just try selecting it again? I'm not 100% sure how to reproduce this. Maybe you have to hit the Apply button in the settings before hitting OK. We'll look into it.
Cuda 9 is currently not supported by DL4J and I unfortunately don't know any timeline when they plan to support it.