Dont push above 2v, you run a much higher risk of damaging the ram.
If Windows will start with 2 modules installed, get a printout of the SPD tables from CPU-Z and set the timings accordingly in the BIOS (use the values for DDR2-800). Make sure you use a command rate of 2t. Install the other 2 modules and see what happens.
If that fails, set each value to the next highest number and try again.
You could also set CPU-NB voltage to ~1.3v and CPU-NB to 2200.
HP-UX. I came, I saw, I was sad it would not run on my X86 box. [Official]AMD RX 480/ 470/ 460 Owners Club