Next week or so, AMD is expected to deliver its Radeon R9 380X. This video card is based on the Tonga GPU and is believed to feature 2048 stream processors, 128 TMUs, 32 ROPs, a core clockspeed of 1070MHz, 256-bit memory bus and 4GB GDDR5 memory clocked at 6125MHz.
According to leaks spotted by eTeknix, the R9 380X will offer performance close to the Radeon R9 290:
In 3DMark 11 Extreme, the card managed to score 4024 overall with a relatively weak Intel Core i5 and 3768 in graphics. The R9 290 scores around the 4200 mark and the R9 280X at about 3300. Based off our estimates from extrapolating Tonga/GCN1.2 improvements over the R9 290X/GCN1.0, we would expect the 380X fall a bit short of the R9 290 but still surpass the GTX 780 in most cases. This is despite the 780 scoring about 3600 in 3DMark 11 since that test tends to favour Nvidia cards more.