You can try and install both DIMMS. The BIOS will default to 1.8v. You should set the RAM to Mfg. specs in BIOS 2.0-2.1v to insure proper function of the RAM. Once you load you OS and MB/chipset drivers the correct voltage will be needed running the system under the load of the software. So set the RAM's voltage, speed and timings according to RAM Mfg. spces in BIOS and your OCZ should do fine with your MB. You have the 650i chipset which tends to be picky about RAM. Setting the voiltage to 2.0-2.1v will very likely be needed for stability with that chipset.