https://wccftech.com/amd-radeon-rx-590-graphics-card-2304-sp/

AMD’s upcoming graphics card, the Radeon RX 590 is going to have a total of 36 CUs or 2304 SPs.

Considering the old RX 580 has 2304 stream processors and is based on the same approximate node (the 12nm FinFET,  is an enhanced version of the 14nm process, even though the name might suggest otherwise)  we are looking at athe same core count and some additional few percentage points because of slightly higher clock speeds. All in all, you are looking at anywhere from 1%-5% real life gain under normal circumstances. This kind of performance level is something we have already seen before, in the leaked FF XV benchmarks of the Radeon RX 590, where it fares a lot better than the RX 580, indicating it’s in fact, the same GPU.