Ram upgrade help

Built my (first ever) machine about 2 years ago and would like to upgrade RAM from 6 to 12g. Motherboard is an Intel DX58SO, with 3 slots only. Just saw 4g modules for sale on Newegg and was hoping folks here could tell me if they'd work properly in my computer. Specs on current memory (per CPU-Z):
Corsair CM3X2G1600C8 DDR-3 dual channnel 2g modules (x3)
Max bandwidth: PC3- 10700H (667 MHz)
Voltage 1.5v at 444, 592, 666 MHz and 1.65v at 800MHz

Motherboard/CPU:
Intel DX58SO X58 chipset
i7 920 2.67GHz processor with socket 1366 LGA

Not sure what other specs are pertinent- please let me know whatever else is needed to figure this out- and thanks very much!