as per
http://www.intel.com/products/mother...GGC2/index.htm
if it is the exact model then it couldnt run at 667 so it will run at 533..
there are only two slots of memory it seems it doesnt support 1gb in 1 slot and 1 gb in 1 slot according to the technical product specification
http://www.intel.com/support/motherb.../CS-029352.htm as there are no mention of the same there.
check your memory section in the motherboard manual