Really slow 3D viewport render preview with gtx-970 I do have a new computer (much better than the previous one) and the preview rendering in cycles render is for taking REALLY long time, 5 samples/sec.

I do have Intel i7, 16gb RAM, MSI gtx 970 (4gb), so no idea why it takes so long time.

Any help? Tried changing to CUDA, changed both in user preferences and in the "render" tab.
When you switch to GPU rendering you need to adjust the render tile size. CPU requires small tile sizes, GPU works better with large ones. Start with a size like 128x128 or 265x256 and see if that makes it better. Make a few test to find an optimal setting for your system