Is it compatible? OCZ Gold Triple Channel + Extra Module = 8Gb Dual

I have a triple channel memory kit, but my motherboard (MSI 790GX-G65) only supports dual channel.

So after so research I've determined I can add a 2Gb stick of ram to my existing triple channel (3x2Gb) kit to have 8gb (4x2Gb) running in dual channel.

What I need to know now is if the stick of ram I'm looking at is compatible with my existing ram.

The current ram I'm using is:
OCZ Gold 6GB (3x2GB) DDR3 PC3-10666C9 1333MHz Low-Voltage Triple Channel (OCZ3G1333LV6GK)

The extra stick I'm looking at for £5 is:
OCZ OCZ3G1333LV2G 2GB DDR3 PC3 10666 1333MHz

Could I add extra stick to the triple channel kit to give me 4x2Gb in dual mode or is it not compatible?

Cheers