Never seen a guide and don't know what the delta thing is. Bsaically you can BIOS edit your the clock, '01/03 appear to prefer lower shaders while 05/06 prefer higher shader clocks. For instance the stock BFG original GTX BIOS used 1350 shader while the new OC2 BIOS uses 1458. Shaders move in sync with the core clock so raising the clore clock also raises the shader clock. There are limits however, you can't simly go 400mhz over on shaders and expect everything to be fine, higher shaders can limit max core clocks.