FirePro W9000 is a server GPU based on the 28nm GCN architecture.
It's based on the Tahiti XT Core (same used on 7970) and therefore offers 2048 Shader Processing Units, 128 TMUs and 32 ROPs on a 384-bit interface of fast GDDR5. The central unit is clocked 975MHz while the memory clock operates at 1375MHZ.
Compared to Radeon HD 7970, its central unit is slightly higher clocked but overall its gaming performance is lower than Radeon HD 7970 because Radeon HD 7970 benefits from certified gaming drivers which unlock the GCN's architecture potential while FirePro W9000 is made for professional applications. Therefore, expect its performance to be between 1% and 3% worse than Radeon HD 7970.