7im wrote:That's strange. Why could the onboard driver interfere with the discreet driver? (not looking for a response)
You may not be looking for one, but you're going to get one anyway.
Excellent detective work, suprleg. (Technically, the graphics software, or in your case, firmware, is essentially independent of the code supporting OpenCL, though it may not appear that way.)
When drivers are installed for ATI/NV/Intel, they're generally packaged with component software that intercepts OpenCL API calls and ultimately converts the call to specific instructions that drive their GPU hardware. As long as the code is either 100% independent or any shared code works for any OpenCL call, you won't run into problems, but we've seen similar reports (rarely enough that I didn't think of it) where apparently some part of the Microsoft OpenCL code is improperly intercepting something that should be going through an ATI or NV code path. [Just my unproven interpretation.]
Since the Intel OpenCL code is not supported, removing whatever part of the Intel code isn't needed and/or reinstalling the NV code to restore whatever was (probably) clobbered by Intel will probably fix everything.