NVIDIA didn't share a lot of details but the site speculates Erista may be a smaller derivative of Logan with a Maxwell GPU. After Erista, NVIDIA plans to launch Parker, this chip could be made on a FinFET process and may feature a Denver CPU and Maxwell- graphics.
In related news, FUD Zilla heard from Deepu Talla, the general manager of NVIDIA's Tegra unit, that the Denver processor will generally be faster than what you can expect from a typical ARM Cortex-A57 core.
Since A57 will be the highest performing ARM 64-bit core, the general idea is that Nvidia has to beat that to get some traction. Talla said that we can expect the Denver dual-core Tegra K1 64-bit part to end up faster than A57-based CPU.