Rumors from internet mentioned that the upgrade PS4 (many refers to PS4.5 or PS4K) is codenamed NEO. Unlike PS3 which the changes between generation was only focusing on power consumption optimization due to moving to smaller transistor, PS4 NEO will feature an upgraded. hardware specs as well.
The new PS4 NEO will feature a faster Jaguar CPU core. PS4 features 8 AMD Jaguar CPU Cores clocked at 1.6GHz. PS4 NEO is rumored to feature a similar 8 Jaguar Cores but clocked 500MHz higher at 2.1 GHz. The GPU seems to be most dramatic changes. The older PS4 features an 18 Compute Unit of first generation AMD GCN GPU cores with total Stream Processors of 1152. The clock speed is 800 MHz and the compute performance is rated at 1.84 TFLOPS. However, PS4 NEO is rumored to feature a 36 Compute Unit GPU. That might ended up with 2304 Stream Processors. That is the same amount the rumored specs of AMD Polaris GPU that will be coming on June 2016. If my guess were correct, PS4 NEO will feature a Polaris GPU which will be much more powerful than first generation GCN, probably. Since the compute performance of Hawaii GPU on Radeon R9 290X is rated as 5.6 TFLOPS, Polaris will have to surpass that if AMD did not want to disappoint their customers. So, PS4 NEO might ended up 3 to 4 times more powerful than the original PS4. That is if Sony really use custom Polaris GPU for PS4 NEO. But this is just my guess based on the rumors. The memory bandwidth is also faster at 218 GB/s compared to 176 GB/s of the original PS4. The extra bandwidth will be useful for faster GPU.
While this might sound like a great news for you, this actually isn’t and I’ll tell you why. The difference between hardware will force game developers to develop 2 versions of the game. Perhaps similar to making a same game for PS3 and PS4 but less complex. But the damn thing is, developers will need to optimize the game for 2 different hardwares. That means extra time and extra resources will be needed by game developers, increasing the production cost and slowing down the time needed for developers to create a game. Things are worse for developer like Ubisoft who tend to release a buggy game first and decided to patch a fix later, if they weren’t so lazy.