Take for example SandyBridge Windows 10 inbox driver - 9.17.10.4459. Even if inbox drivers for at least older iGPUs if not all never include an OpenCL CPU runtime, the OpenCL CPU runtime 16.1.1 refuse to install anyway if the graphics driver is there, even if there is no GPU OpenCL support. So on clean, default installation of Windows you have to uninstall the graphics driver, install OpenCL CPU runtime quickly before Windows puts the driver back. You might struggle with this an hour or 2 until you are lucky enough to beat Windows in this race. This is incredibly annoying, as this affects even slightly newer hardware like IvyBridge when you want the latest and greatest OpenCL CPU runtime. OpenCL CPU runtime installer clearly needs improvement as there are some cases where it can be safely installed despite graphics driver presence.
Bug Report