Either turn it off with the -G option or replace the EXE with this fixed one until 3.1.1.
Thanks now it works again. One problem though:
Intensity settings > 0 don't seem to have a lot of effect (compared to 3.0.2)
Intensity settings < 0 reduce GPU usage properly but consume huge amounts of CPU (2 cores 100%)
Dynamic works great (low CPU usage, good hashing performance)
Tested with Catalys 13.4 on Win 7 x64 and
[2013-06-15 17:51:41] CL Platform 0 name: ATI Stream
[2013-06-15 17:51:41] CL Platform 0 version: OpenCL 1.0 ATI-Stream-v2.1 (145)
[2013-06-15 17:51:41] Platform 0 devices: 1
[2013-06-15 17:51:41] 0 Cypress
[2013-06-15 17:51:41] CL Platform 1 vendor: Advanced Micro Devices, Inc.
[2013-06-15 17:51:41] CL Platform 1 name: AMD Accelerated Parallel Processing
[2013-06-15 17:51:41] CL Platform 1 version: OpenCL 1.2 AMD-APP (1124.2)
[2013-06-15 17:51:41] Platform 1 devices: 1
[2013-06-15 17:51:41] 0 Cypress
[2013-06-15 17:51:41] GPU 0 ATI Radeon HD 5800 Series hardware monitoring enabled
[2013-06-15 17:51:41] 1 GPU devices max detected
Maybe it is related to the debug build?
EDIT: when looking at bfg's threads there are the two gpu threads that seem to use all the cycles:
atiocl64.dll!clGetSamplerInfo+0x36a80
They also exist for dynamic intensity but only with 0.5% CPU instead of double digits.