Thanks for the reply. I think my vga is faulty (tryed on 2 monitor e 2 different pc, linux and windows). Black screen (monitor in stand-by) after 10 second from OS boot (but the pc continue to work). The vga work only in the Mainboard Bios screen. Artifact on screen.
So, I want to try to decrase frequency on the VRAM.
I can't download the bios from my VGA (not possible in 10 second of operating system), so i want to download a bios and edit it, and i need to flash in dos.