I am using a ACER EM61SM/EM61PM motherboard with phoenix BIOS. My processor is AMD athlon 64X2 at 2.2 Ghz. The computer has a pair of 1GB DDR2-5300(667Mhz) installed when I bought it. the cpu-z is showing
CPU
Core Speed: 2200mhz
Multiplier: X11
Bus Speed: 200.9 mhz
HT link: 1004.5
Memory
Frequency: 200.9 mhz
FSB/RAM: CPU/11
the memory is only running at 200x2=400mhz!!!!!which is the speed for DDR2-3200!!!! I then took out the memory and installed a pair of 1GB DDR2-6400(800Mhz), the memory speed still stays at 200x2=400Mhz..!!!!! I think the problem is the FSB/RAM divisor...it is stuck at 11, the memory speed will always be my processor speed/11 which is a dead 200Mhz. Is there a way to change the divisor? I see no option in my CMOS setting or BIOs setting... where is the option usualy under? Or is there a switch on the board itself? or basicly it is a normal condition. Thanks so much!!!

any solutions?

An aftermarket board would have the setting in the BIOS; however, Acer, Dell, and other computer manufacturers normally have the BIOSes on their MBs "crippled" to remove the ability of users to change these settings.
If the standard memory speed on your system is DDR2-400, chances are that the MB design wouldn't support error-free operation at DDR2-800, anyway.