Gigabyte is adding overclocked versions of Nvidia's GTX 970, 980, 980 Ti, and Titan X to its Xtreme line of GPUs, with higher factory overclock settings than their usual cards. Even with a hefty overclock out of the box, these cards are equipped with the cooling and power to boost them even more if you want. These cards are also about looks: they're decked out with programmable RGB LEDs.
According to Gigabyte, the various graphics cards have had their performance boosted as follows:
The stock GTX 970 has a clock speed of 1050MHz, which can be boosted to 1178MHz. The $380 Xtreme Gaming version starts at 1190MHz, with a boost speed of 1342MHz. That's only a bit faster than Gigabyte's GTX 970 G1 Gaming, but with more expensive internals and dual 8-pin power connectors instead of an 8-pin and a 6-pin.
The stock GTX 980 has a clock speed of 1126MHz, which you can boost to 1216MHz. Gigabyte's new $530 version starts at 1241MHz, with a boost speed of 1342MHz.
There are two versions of the GTX 980 Ti available in the Xtreme line, one with air cooling ($700), and the other with a water cooling block ($720) which cools the VRAM and MOSFET in addition to the GPU. The new versions of both have a base speed of 1216MHz (up from the stock 1000MHz) which can be boosted to 1317MHz (up from 1075MHz).
Finally, the GTX Titan X has a base clock speed of 1000MHz, which can be boosted up to 1075MHz. With the Xtreme line, this will be pushed up to a base of 1165MHz, with a boost speed of 1266Mhz.
As for cooling, the four non-water cooled cards have Windforce 3X cooling, and with the Titan X and 980 Ti cards the middle fan spins the other way to the others, which Gigabyte says helps to dissipate heat.
The new cards are all available from the Gigabyte store, where you'll also find more detailed specs.