For 2 years already, am still to no purpose looking for the 16GB of DDR2-1200MHz memory for my Asus P5Q Premium mother. Is the ASUS' promise real at all?
Check the manual of the mobo or contact with ASUS support, some mobos, specially old mobos has chipset limitations and will not recognize the full 16GB, even if the pages says that is supported.
Thanks for calling. Also no techno-geek myself, I should say ASUS P5Q Premium's design is probably no more than 2.5 years old and it is the top one within that P-45 /ICH-10 line ... The question was NOT "whether it DOES support 16Gb of DDR2-1200"! The question is WHERE TO BUY 16GB of DDR2-1200 (or -1066) in four "4GB single chips". Those talking to ASUS directly - by thelepathy - for their "iron"'s support cloud or those deep in high DDR-2, I pray to you for info rain...
You won't see any difference between 800MHz, 1066MHz or 1200MHz. But I suggest to you, don't waste your money, 16GB DDR2 now are more expensive that DDR3 and don't performs the same.
The price will be $360, with that price you can buy a SSD, Six core AMD or new GPU.