VR World has a bit of background information about why Sony decided to go for a "PlayStation 4.5" console. The author claims that while previous-gen consoles received hardware updates via simple die shrinks, moving the current gen consoles from 28nm to 14nm FinFET didn't turn out to be that easy. Neither Sony nor Microsoft were ready to pay for the cost of the die shrink, which would involve development fees in the range of $120 million to $220 million.
In order to optimize the PlayStation platform for virtual reality, which currently involves a mess of cables and what appears to be a second video processing unit, Sony reportedly pulled the trigger to go ahead with a bigger overhaul than it initially planned.
The PlayStation Neo will reportedly feature a 14nm FinFET APU from AMD, with low-power "Zen Lite" cores clocked at 2.1GHz and a new graphics solution derived from Polaris. The article describes these low-power Zen cores as the successor to Puma.
According to sources in the know, the Polaris for PlayStation Neo is clocked at 911 MHz, up from 800 MHz on the PS4. The number of units should increase from the current 1152. Apparently, we might see a number higher than 1500, and lower than 2560 cores which are physically packed inside the Polaris 10 GPU i.e. Radeon R9 400 Series. Still, the number of units is larger than Polaris 11 (Radeon R7 400 Series), and the memory controller is 256-bit wide, with GDDR5 memory running higher than the current 1.38 GHz QDR. Given the recent developments with 20nm GDDR5 modules, we should see a 1.75 GHz QDR, 7 Gbps clock – resulting in 224 GB/s, almost a 20% boost.
The PlayStation Neo may ship towards the end of the year, in time for the arrival of the PlayStation VR headset.