Just been looking on Corsairs site. They recommend you don't put more than 2.1v through them (but they would have course) 
Interestly enough are some of the recommended settings for these modules such as:
MCH = 1.65v
ICH = 1.2v
tRFC = 52
tRRD = 10
Rank Write to Read Delay = 10
Read to Precharge Delay = 10
Write to Precharge Delay = 10
tRFC is the tricky one since a lot of motherboards don't go past 42. Apparantly either leave it on auto or set to the highest setting.
It seems that one of the keys to successfully overclocking this ram is the tRFC due to the high density of the ram chips.
I can't remember what my mobo settings adjust to but I will be having a play with them tonight.

Interestly enough are some of the recommended settings for these modules such as:
MCH = 1.65v
ICH = 1.2v
tRFC = 52

tRRD = 10
Rank Write to Read Delay = 10
Read to Precharge Delay = 10
Write to Precharge Delay = 10
tRFC is the tricky one since a lot of motherboards don't go past 42. Apparantly either leave it on auto or set to the highest setting.
It seems that one of the keys to successfully overclocking this ram is the tRFC due to the high density of the ram chips.
I can't remember what my mobo settings adjust to but I will be having a play with them tonight.