I just want to share...

well ..we know it reverence VGA HD 5870 have limit on memory clock 1200 -1300 but with RBE we can edit and memory can run higher than 1300

1. RBE ( Radeon Bios Editor ) http://de1-dl.techpowerup.com/Utilities/RBE/RBE_125.exe

2. GPU Z ... http://us3-dl.techpowerup.com//SysIn...PU-Z.0.4.3.exe

save your VGA bios from GPU Z
The complete guide is HERE