The 4870 GDDR5 should get around 12.5K in 3D 06 at stock, at least according to the specs (and not the fake numbers). As for performance, it should be able to equal the 8800 GT 512MB in the games in which the 3870 lagged behind.

We will also see larger performance gains from overclocking due to the greater number of shaders. Should be interesting, but not mindblowing.

Perkam