Radeon HD 3870 Game Requirement Analysis
Radeon HD 3870 is a high-end GPU based on the 55nm, second unified shader architecture, R600.
It's based on the RV670 XT Core and offers 320 Shader Processing Units, 16 TMUs and 16 ROPs a 256-bit memory interface of energy efficient GDDR4. The central unit runs at 777MHz and the memory clock runs at up to 1126MHz.
Compared to Radeon HD 3850, it offers extra bandwidth (thanks to the higher operating memory clock resultant from using GDDR4) and the central unit is higher clocked. However, it also consumes up to around extra 30W. This value would be higher were standard GDDR3 used.
Today's modern games should run fluently at medium settings but with modest resolutions. DirectX 11 games aren't supported.