Ok, I thought assembling a PC from parts was a nobrainer. Pick what you want, assemble and it should work. Standards are there to that purpose.
Well, no quite. I just got caught with DDR2 rams. Picked the mobo, proc,... and that fast DDR2 ram. No Boot, beep, beep, beep....
A few tries... Swapping the ram from another PC, and bingo all run nicely.
A bit of investigation later, arghhh, the mobo supports ram voltage up to
1.95V and is defaulted by the bios to 1.8V while the fast ram wants 2.2V
Now the PC runs with the new ram at 1.95V but of course with degraded timings. Of course all those voltage limitations aren't in the mobos manuals (you have to discover this once all is installed) so it'll be a pain to RMA it and look for another one that fits.
OTOH it's easy to modify the ram vdd controller to get the required voltage, but... the question is how are handled the signal levels WRT to the other elements on buses? I've noticed on some datasheets there's a reference voltage input on the DDR2 ram chips, but that doesn't tell all the story, so... Is there more to change the ram supply voltage than simply changing it or can I go safely with this?
Any enlightened hint?