DDR2 RAM 4x1GB or 2x2GB

[Multi-Boot]

Which option should i opt : DDR2 RAM 4x1GB or 2x2GB Please help me with this. What will be the difference between the first and the second case? Can anyone help? I have a Gigabyte Motherbard with 2 RAM chips of 1 Gb 667 in dual channel. I have switched to a 64bit system and feeling the need to increase ram and want it to be 4 GB Total. At this point do I take another 2 Chips of 1GB? Will it causes me problems? Or do i go for 2 chips of 2 Gb? Current RAM is working at 667 does that make sense if i take the 800 Mhz ram? Can i force them all into 800Mhz? Please help...

[Rudra.J]

Usually, most motherboards has the ability to set different speed for the ram dividers so as to force them into asynchronous FSB compared to the processor... If you need to overclock to the point where I find them should you take to other two 1GB chips to make it 4x1GB but if a 2x2GB kit is cheaper but you can force the RAMs to work in same frequency, but in such case, the frequency of the RAM which is lower will be used and not the frequency of the RAM which is higher...

[Patio]

Have a look at some similar topics, may be you could gather some help :
DDR2 1200 MHz or DDR2 800MHz with lower clocks ?
http://forums.techarena.in/xp-hardware/1095973.htm
is it possibleto use DDR2 DIMM RAM with DDR2 SDRAM?

[Solomon]

The ram is in asynchronous, I know that goes that way, but usually I have always seen the asynchronous Ram / CPU is a disadvantage relative to the ram that is slow ram + CPU which is higher, I do not know if you can do the opposite as it is the processor that generates the clock and not the Memory... Hope this is helpful...

[Multi-Boot]

Then from what I understand the frequency of the RAM bus is generated by a contant divider calculated with CPUs frequency rather than the FSB. I know fsb is an inappropriate term, but to understand each other. So I can still take advantage of 800 MHz compared to the CPU which is 2600, would end the 742 mhz ram but should work better than in 667. If this is the case then it is worthwhile to upgrade to 2x2GB 800MHz instead of 667...