CUDA SDK + OpenCL performance

Dec 11, 2015 at 5:18 PM
I've been playing with CUDAfy and running in OpenCL mode and noticed today that after I installed the CUDA SDK to try out CUDA mode the performance in OpenCL mode was around 70% worse. Uninstalling the SDK and re-installing the current NVidia driver returned the OpenCL performance back to it's previous level. Is it just an older driver with the SDK or is something else causing the slowdown ?
Dec 13, 2015 at 1:18 PM
That's indeed weird!
I wonder if installing the sdk made the default opencl driver a software-implemented one? Did you notice your cpu spiking while running the slow opencl?
Once you get an instance of an opencl object, you can query it about its properties, including its name and description. You may want to compare its output pre vs post sdk install.