Originally Posted by DMatthewStewart
Ive been contemplating flashing one of my Lightnings since this posted. I dont think I have the guts to chance it
Originally Posted by diggiddi
Tried it once, wasn't too successful but I prolly didn't stick with it long enough
Personally I'd recommend modding your factory roms to have tighter ram timings. Clock for clock I can beat a 390X for 3dmark FS graphics score by 3% with my modded factory rom, this is also true for Valley, not had time to test other benches.
Your PCBs differ vastly to ref 290/X and 390/X, besides Lightning only Matrix have software memory voltage control, AFAIK no other 290/X or 390/X support this feature.
Reading how Stilt optimised VRM efficiency in his ref PCB 290/X roms (I think in VoltageObjectInfo table) I'd be hesitant to use roms which may not support same design VRM as on PCB. Your cards have got way more phases than 290/X & 390/X, I think my Vapor-X 290X has 10+2+1 and been hesitant to try a 5+1+1 (ref 290/X) or 6+1+1 (most 390/X) ROM.
The only 2 things in a 390/X rom that differ IMO are RAM timings and how the Stilt stated they optimised memory controller via bios to achieve higher RAM frequency. I've modded a complete VRAM_info table from 390X rom into my 290X rom and changed RAM IC timings to what mine are and see no addition headroom in RAM OC frequency.
I also started a compare of command tables from 390X with 290X and so far all I've checked are the same and to me only data tables vary.
Basically why command tables are not varying is:-
There are two sets of tables in ATOM: command tables (basically scripts that execute certain functionality) and data tables (structs that store board/system specific information (type and number of connectors/encoders used on the board, power states, ddc lines, panel info, etc.).
Link:- quote source, view info under heading AtomBios infoEdited by gupsterg - 11/19/15 at 4:59am