reviews seems pretty mixed on this one but for reference, this should give you an idea how it performs against the recently released R9-295x2
notice in the testing though, no mantle api tested
AMD Radeon R9-295x2 Review - Interim Nvidia 337.50 Driver update
and something to take note from the results at HardOCP
With the GeForce GTX 780 Ti we found the peak consistent clock speed on both GPUs went up to 1019MHz while gaming. This is higher than the boost clock on a GTX 780 Ti which is 928MHz. As we posted on the previous page, this seems slightly higher than we've tested in the past.
Normally we've seen the GPU hit 1006MHz while gaming, but now it is at 1019MHz with this newest driver. We also noticed the temperature of the GPU was higher, at 87c, versus 84c on previous drivers. This higher temperature threshold has allowed the frequency to go higher, hence the 1019MHz. In any case, this means the GTX 780 Ti SLI configuration was providing us higher performance for this round of testing, so it definitely got to give us its best shot at stock performance without overclocking.
hope reviewers will look into this