Oracle has published an update to the Processor Core Factor Table
that lists the (yet to be released) T4 CPU with a factor of 0.5. This leaves the license cost per socket the same compared to T3 and puts T4 in the same league as SPARC64 VII+ and all current x86 CPUs. We will have to wait for the announcement of the CPU until we can actually speak about performance. But this core factor (which is by no means a measure of CPU performance!) seems to confirm what the few other available bits of information seem to be hinting at: T4 will deliver on Oracle's performance claims.