According to one report, if the "Moorefield" processor is indeed chosen, the PowerVR G6430 GPU would be employed for the slate. The latter is said to be 20 times faster and five times more efficient than the Series 5 models.
Intel has already announced a partnership with Asus, the manufacturer behind the first two Nexus 7 slates, and one of the companies always rumored to be behind a Nexus 8 model. And with Asus and Intel working hand in hand this year to build a line of smartphones and tablets, an Asus branded, 64-bit octa-core powered, Nexus 8 tablet with Intel Inside could very well hit the market sometime later this year.
source: AndroidPit via BGR