Just wanted to let you know that I've updated my i7 2600k PC with a GA-Z68X-UD5-B3 motherboard and 16Gb 1600 memory from a Radeon HD 5450 to a ASUS Geforce GTX 660 DCII Top nVidia graphics card and I'm pretty satisfied with it. Much quicker editing and rendering, stable PC without PD11 hanging all the time and also nice and quiet. Latest driver seems pretty stable too.
All in all a good decision to invest in this graphics card.
Cheers,
Harry