@micham

Perhaps it might be a good idea to read the Release Notes 

Specifically I noted this myself:

Limitations -

This beta software release introduces a CPU only runtime package with OpenCL* 1.2 features support. When installed on computers with 3rd Generation Intel® Core processors with Intel® HD Graphics on Windows* OS, this non-conformant OpenCL* 1.2 CPU device works in a platform mixed mode with the conformant OpenCL* 1.1 device available with the Intel HD Graphics 4000/2500.

List of Changes -

Compliant with the Intel® HD Graphics WHQL Driver for Windows 8* OS (version 9.17.10.2792) on Intel HD Graphics 4000/2500. This SDK release will not work with previous graphics drivers.  

Support for OpenCL* 1.2 features on CPU device only.

Known Issues -

• With support of mixed versionof platform version, you can work with:      
  • single device contexts
  • multi-device contexts
  • homogeneous platforms (for example, with all devices with the same device version).

• The only exceptions are:      

• With the Intel® HD Graphics-only context or a multi-device context (Intel HD graphics and CPU devices) the OpenCL* 1.2 APIs return CL_INVALID_DEVICE as return code. Consider using the OpenCL* 1.1 APIs only.
• Existing OpenCL* 1.1 APIs, which use OpenCL* 1.2 features, such as, clEnqueueNDRangeKernel with 2D image array argument, fail with appropriate return codes, for example: CL_INVALID_MEM_OBJECT.

• Shared context (the OpenCL* context which includes both CPU and GPU devices) limitations:      
  • Avoid using OpenCL* 1.2 API's on shared context.
  • Do not trigger for both devices (specify NULL as device_list parameter).
  • Avoid using images with CL_MEM_USE_HOST_PTR flag.
  • Avoid using on systems with discrete graphics.
  • Avoid calling clEnqueueMapBuffer[Image] on one device while calling clEnqueueUnmapMemObject on the other device (while this is enabled by the specification).
  • Use image formats supported by both devices only.

Cheers