Capture One V7 - Engine 7 doesn't use OpenCL [Open CL]

Hello to everybody here,

I am an absolute convinced user of Capture One for many years now (also in the time, C1 was a disaster when starting V4). At this time I am using V6 Pro and I am testing at the moment V7. Here is my problem with V7:

If I use Engine 6, everything is working fine: screen update and development is using OpenCL and is pretty fast.
Using Engine 7 there is absolutely no activity on the graphics adapter. It looks as if OpenCL is not activated (but both are set to "auto"). The results with engine 7 (e.g. highlight recovery) are much better as with engine 6 but the software is nearly not applicable without OpenCL working (when developing a picture you can’t do anything else because system is busy 100%, also developing pictures needs about 10 times longer.

I have no idea why OpenCL is working with engine 6 but doesn’t with Engine 7.
My System:
Win7 64 Bit
16GB RAM
i7-2600K running with 4315 MHz
ASUS P8P67 Deluxe
Gainword NVIDIA GeForce GTX 580, 3 GB with newest DisplayDriver 306.97

Anyone an idea here in the forum? I also started a case in the support team today.

Regards

Marc