Trying to understand the technicial differances between both cards...

4870x2  =1600 Stream Processors               5870 =1600 Stream Processors

 85 Mhash/s Core 0  56-70 Mhash/s Core 1                  350-390 Mhash/s Core 0

 DDR3 with a 256x2 (512-bit bus)                                DDR5 with 256-bit bus 

 ROP's 16x2 (32)                                                        ROP's 32

 Texture Units 40x2 (80)                                             Texture Unites (80)

 32-bit floating point                                                   32-bit floating point
           
In nearly all directx 9 and 10 games the 4870x2 and 5870 are Neck in Neck.


It puzzles me that the 4870x2 does so very bad in compairison to the 5870 when memory speed and bandwith are absent requirments... only raw processing power is needed.  I would expect to lose a certain percentage of computing effecency between core 0 and core 1 on the 4870x2 but to have a 250% preformance difference in these 2 video cards?


Maybe we need someone who can write custom drivers or an application profile for bitcoin mining? Owning 4 of these cards myself, I would be willing to put up a bounty.