First time build, n00b question.

[Digimortal]

I just ordered a new mobo, PSU, CPU and case and I completely forgot to leave myself some extra cash to order the RAM as well (I feel like an idiot). My current system already has 7GB PC2-6400 DDR2 SDRAM but the memory standard on the motherboard I ordered is DDR3 2000(O.C.)//1600/1333/1066. They are both 240 pin but I'm just wondering if it will actually be compatible...

I am still planning on definitely upgrading to 16GB DDR3 but I can't for a little while, maybe a month, so I definitely need SOMETHING to hold until then. Any help or advice would be greatly appreciated

 

[Slaymate]

DDR2 and DDR3 are not interchangeable.