Take with a huge grain of salt but theres also an unboxing video!
Source
All of the chips that are featured in the new Radeon 300 series lineup make use of new naming schemes for existing GPUs. For instance, the Radeon R9 390X is based on the Grenada XT (Hawaii XT) core that has 2816 stream processors, 176 TMUs and 64 ROPs. The card packs a clock speed of 1100 MHz on the MSIs Gaming model and has the 8 GB GDDR5 VRAM clocked at 6100 MHz that runs across a 512-bit wide I/O interface. The chip has a 208W TDP which could possibly be a mistake since Hawaii has a TDP range of around 280W and MSI also listed the same TDP for the reference Hawaii cards (290X) during launch which turned out to be a marketing mistake. The more surprising bit is that the Grenada Pro is also based on the Hawaii XT core die but has lower clock speeds on the core of 1060 MHz while the other specifications remain the same. Both top end cards feature the latest Twin Frozr V heatsink which will deliver adequate cooling performance to Hawaii and features Dual-DVI, HDMI and Display port connectors.
Source