Earlier this year, Mediatek announced one of its first ARMv8-based SoCs, the MT6752, that also has integrated LTE. The Oppo U3 seems to be one of the first devices to use it, as seen on the GFXBench website.
The benchmark unveils a MT6752 SoC that comes with powerful Mali-T760 GPU (same as in the Galaxy Note 4) and a CPU that has eight Cortex A53 cores. Apparently all eight are clocked at 1.7 GHz, unlike Qualcomm’s Snapdragon 615 which only has four Cortex A53 cores clocked at 1.5 GHz and four at 1.0 GHz. It’s unlikely, though, that Mediatek’s cores can all be powered up at 1.7GHz at the same time, or for extended periods of time.
The MT6752 is also a chip that comes with integrated LTE, representing an even bigger danger to Qualcomm, which has historically dominated the mobile LTE market thanks to its integrated LTE chips. While Qualcomm has integrated LTE into its chips using a top-to-bottom approach, Mediatek seems to be doing it in reverse, releasing chips that are increasingly more high-end and have LTE.
Although the MT6752 is certainly an ARMv8/64-bit chip, the benchmarks shows it as "ARMv7". This is probably because the device is still running in the 32-bit mode. Plus, right now it’s uncertain if the Oppo U3 will even arrive with the 64-bit-enabled Android 5.0, or if it will keep the OS it’s currently being tested on: Android 4.4.4.
The Oppo U3 will also come with 2 GB of RAM, a 4.6” screen with 1080p resolution, a 12 MP camera on the back capable of 4k video recording, and a 4.7 MP front-facing camera that’s capable of 1080p video recording. Availability is unknown, but it should be announced in the next couple of month.