it really depends on the chips.
i have week 37 TCCD and they like 3.0/3.1 volt...i run very tight timings and ~290 fsb and 2.7 or so volts i cant even boot right now.
i dont like pushing them w/ 3.1V, but everything looks fine and w/ less volts i get BSODs etc.
AS A RULE - many people told me TCCD does NOT profit from anything over 2.9..but then there seem to be exceptions. Be careful !!!
Maybe as the UPPER, upper limit (of course with a fan blowing over the memory !) you can risk upping to 3.2 if you see any benefits from
going over 2.9.