OCZ OCZ3X13334GK PC3-1066 DDR3 1333MHz Intel Extreme 4 GB Dual Channel Kit DDR3 1333MHz XMP Profile 1: 1333MHz 7-7-7-20 1.75V XMP Profile 2: 1600MHz 9-9-9-28 1.8V Intel Black XTC Heatspreader Optimized for Intel X38/X48 Chipset