Memory from board to board will work differently (memory speed or fsb) and at different voltages. I presume a lot has to do with the trace wires embedded in the board, regulator and just the quality of the parts. Don't get me wrong, I still think that the 4G4A+ is a very solid and stable board. If you do raise the voltage, it would be a good idea to provide some form of active cooling for the memory sticks. I don't believe in heat spreaders myself because I found out by removing the spreader, even with active cooling, air blowing right on the heat spreader, I was able to increase the output of the memory speed by about 2-3 mhz (FSB wise). If you ever took off a spreader on a stick of memory, you would understand why. They use a fairly thick double sided tacky tape to attach to the IC chips and then to the spreader plate. I presume heat transfer through the tape was very minimal and therefore, allows heat to build around the IC chip. That is why I buy Samsung, even if it is DTL stuff. They don't put any HS on their memory except Mushkin does it for theirs, which uses Samsung. Even the DTL stuff is good. I've heard some give that latest release a thumbs down. I heard and then discovered the DTL stuff likes voltage, so that must be the difference between CTL and DTL. CTL stuff would crap out (at least on my Abit KR7A) above 2.95V while the DTL will work all the way to 3.2V on the 4G4A+.
As far as PS voltages, you should measure with a voltmeter for the 5 and 12 at the HD plug-in and then at the ATX Molar plug-in. At idle, as a minimum, you should see around 5.15 and 12.3. Under load the 5 will definitely drop by 0.15 and the 12 will move also. Since this board doesn't have the common Intel 12V plug, it becomes very important both 5/12 are supplying the proper voltages in idle and under a load. Don't forget, all manufacturers design their products to sustain a plus or minus 10% from the nominal voltage. So, you can be as high as 5.5 for the 5V and 13.2 for the 12V, and still be within allowable tolerances. Actually, higher voltage will produce less heat within the device.