We do not have yet on the market smartphone with MediaTek Helio X20 and X25 chipset, but the first rumors about their successor, i.e. Xelio X30 SoC, appeared in the web. Currently, Helio X20, i.e. the first MediaTek a tri-cluster deca-core processor is ready for mass production. Meizu MX6 will be probably the first smartphone with this SoC. The Helio X25 will be inside upcoming LeTV Le2.
So, we did not have an occasion to see Helio X20 and X25 chipset in the action and we already are talking about their successor. The latest information suggest that we will see the first X30 smartphone in early 2017. I have to admit that the work speed of MediaTek is amazing.
What is new in Helio X30? I did not find any official information or comment from MediaTek, so you should treat this as a rumor. Helio X30 will be tri-cluster CPU design with 2x Artemis cores clocked at 2.8 GHz, 4x Cortex-A53 cores clocked at 2.2 GHz and 4x Cortex-A35 cores clocked at 2 GHz. Generally, the new Artemis core is the successor of Cortex-A72 and will compete with Kryo solution from Qualcomm. Also, Cortex-A35 is very power efficient solution which is 40% faster than Cortex-A7 in the previous MediaTek chips.
What else? You should expect also much better gaming performance thanks to 4-core PowerVR 7XT GPU which supports 26 MP snappers, dual camera setups and VR (Virtual Reality). From connectivity point of view, MediaTek Helio X30 will be LTE category 13 device, i.e. with support for LTE-Advanced standard.