The SD 845 will come with A75 and A55 cores with BIG.Little architecture. The Cortex A75 core has 20% boost in performance over Cortex A73 and 40% greater than the A72 core.Power consumption will be similar to Cortex A73 core.The Cortex A75 core is far ahead than the Cortex A73 cores in GeekBench v4.0.The Cortex A75 core can be clocked speed up to 3GHz a 200MHz upgrade over the A73 core.
The Cortex A55 cores will provide twice the performance than A53 cores and 15% improvement in power efficiency. The A55 can cluster 8 cores in a single cluster which is the first core to come with 8 core in a single cluster.With SD 625 there are 8 cores of Cortex A53 with two cluster of 4, with A55 we can now make a single cluster of 16 cores packed with two clusters which improve the battery life of the device.Even Cortex A55 cores were benchmarked which even outscored the A53 cores.
The SD 845 will be 30% improvement in Single core threading and 70% increase in multicore threading. Sd 845 might be announced this year but will be available only first half of 2018.
We have to see how will it perform in real life usage and have to wait what Mediatek will do with this news.