Ok I've tried everything you guys suggested (and then some) and while I think I'm close to cracking this one I need some more guidance.
The revelation from todays tinkering is that I can now run 3 sticks of ram (i.e. 6Gb total) with the following settings:
- (All the changes from the first post, plus)
- Performance Enhance - Standard (default Turbo)
- Extreme Memory Profile (X.M.P) - Disabled (not sure if this was the default)
- DRAM Timing Selectable (SPD) - Manually set to 4-4-4-15
- Advanced Timing Control - All Auto except tRFC set to 54
- MCH Core - 1.4 (default 1.1)
- MCH/DRAM Reference - 1.00V (default 0.75V)
- DRAM Termination - 1.0 (default 0.9)
- Channel A Reference - 1.0 (default 0.9)
- Channel B Reference - 1.0 (default 0.9)
Other things I've tried that made no difference (in trying to get the 4th stick to post):
- Increasing DRAM voltage to 2.2 (the rest of the RAM related voltages changed automatically to half this value, i.e. 1.1)
- MCH Core - 1.5V
- System Memory Multiplier - reduced to 2.5A, i.e. running RAM at 667MHz
- DRAM Timing Selectable (SPD) - Tried going as high as 6-6-6-18
From my progress today I believe that I am close, as until today I was unable to run with three stick, but I feel that there is a particular voltage setting that I have not tried tweaking. This is why I need your help, everything I've tried so far points in the direction of the voltage being the problem, i.e. not enough juice to run all for sticks. So, what am I missing?
Dave, thanks for your suggestions, as you can see I've tried everything from your list, unfortunately it wasn't enough. Just to be clear I have gradually changed settings trying to see if any one in particular would help (this is how I discovered that I can run 3 sticks) so at the end I had my RAM running at 667MHz with 6-6-6-18-54 timings, with extra voltage (2.2V Ram 1.5V north bridge core).
Thanks for your continued support!