ASUS announced as many as five GeForce GTX 660 Ti graphics card models. The cards are based on the company's dual-slot DirectCu II cooling solution, and a PCB design that's similar to that of the GeForce GTX 670 DirectCu series. Among the five models are the GTX660 TI-DC2-2GD5, the base model that sticks to NVIDIA reference clock speeds of 915/980/6008 MHz (core/boost/memory); the GTX660 TI-DC2O-2GD5, with a mild level of factory-overclocking, at 967/1058/6008 MHz; GTX660 TI-DC2T-2GD5, or TOP variant, with 1059/1377/6008 MHz; and variants of the GTX660 TI-DC2O-2GD5 and GTX660 TI-DC2T-2GD5 that feature Steam coupons to Borderlands 2 game. Based on the 28 nm GK104 silicon, the GeForce GTX 660 Ti packs 1344 CUDA cores, 112 TMUs, 24 ROPs, and a 192-bit wide memory interface, holding 2 GB of memory. ASUS' cards uses two 6-pin PCIe power connectors to draw power. Display outputs include a pair of dual-link DVI, and one each of HDMI and DisplayPort. The cards are 3-way SLI capable. The DirectCu II cooler uses a compound heatsink to which heat is fed by a number of copper heat pipes, which make direct contact with the GPU. ASUS plans 3 GB variants of the same models, in which six 2 Gbit memory chips make up 3072 MB of memory, with 144 GB/s memory bandwidth.