We tested with Team DDR2133 4GB memory which requires 1.65V without any problem. If you want to change the memroy setting inside the BIOS, you can go to the M.I.B III page inside the BIOS. Change the Performance Memory Profiles to Manual. Then, you can adjust the memory setting.
There's no voltage option though, only timings and frequency. I can change my ram's freq to 1600 mhz, but it won't boot and I had to reset the cmos.
I don't see how you could have used a ram rated for 1.65v when this motherboard seems to only be capable of around ~1.5v. Unless of course, I'm missing something.