Recent reports from various sources suggest that NVIDIA would be launching a trio of mid-range GPU's in September - GTX 660, GTX 650Ti and GTX 650. Currently, NVIDIA has GTX 660Ti planned for launch on 16th August.
The GTX 660 and GTX 650Ti come with the GK106 core architecture, Exact model being GK106-200-A2 on GTX 660 which has a core count of 1152-960 Cores, 2GB 192-bit memory and comes at a price of $229 US.
The GTX 650 Ti comes with a core count of 768-960 with 1GB of GDDR5 memory. This model would cost $155-$159.
Last of all is the GK107 based GTX 650 which is a GDDR5 version of the GT640 GPU featuring the same specifications of 384 cores, 1GB 192-bit memory and faster clock frequencies in addition to a 6 Pin connector to provide power.
All GPU's launch within September during the 3rd Week while the GTX 660Ti launches next week.