Originally Posted by Golden Flamer
Great mod celemine!
I see that my max VDIMM Voltage oin this board is Vsource - 0,2V. My 3,3V is 3,35V, so my max VDimm is about 3,16V without any mod. With this voltage my Best BH-5 RAM (768 Mb Total, 1x512Mb Corsair PC3500 stick, + 1x256Mb Mushkin Lvl2 PC3200 Bh-5 Stick) can do about 251MHz at most aggressive timings.
I don't have time to analize the circuit, but I think ABOUT A LINK BETWEEN PSU 3,3V RAIL and VDIMM MEAUSER POINT ONE THE MOSFET PIN. WHAT DO YOU THINK ABOUT THIS, IS THIS POSSIBLE?
If This mod work I think RAM become always filled with full 3,3V RAIL, This should cut off all the RAM's Voltage Supply Circuit. VDimm become fixed at the 3,3V rail value.
Is this dangerous?
Don't do this!!! It could possibly destroy some of your hardware. If you really want to mod the board in order to always feed VDimm with the 3.3v-rail directly, then do it right. I had the following mod running for a day while working on the 5V-mod described above. The 5V-mod wasn't done yet and I had to get the board up and running for a quick test so I did the vdimm=vio mod (i.e. vdimm = PSU's 3.3V-rail).
But if you do this you should also remove "Q50"'s source-pin from the PCB (in order to keep the mosfets alive). Then you check the capacitors next to the VDimm slot with a multimeter set to continuity test for connections to "Q38"'s source-pin (this pin is one of the VDimm measuring points, too). If you have found the two capacitor contacts, solder wires to these capacitor legs and not directly to any pin carrying vdimm! Doing it my way will give you clean, filtered voltage instead of having unfiltered, perhaps a bit fluctuating volltage directly from the PSU.
But I didn't describe that mod before because I don't like it very much and I don't think that it's optimal. You can't set vdimm to anything lower or higher than your 3.3V rail, thus you are still very limited.
That's exactly why I came up with my 5V-Mod.