>Thanks for your reply,
>
>Let's see if i understood....You're saying that i can get PC3200 (400 mhz FSB)DDRAM modules and place them into older mobo even if they don't support these speeds?

Yes.

>I understand that i can not place 333MHZ and 400MHZ DDRAM modules together for example, they're not compatible and system won't boot, is that correct?

No, that's not correct - see below.

>
>Would I place PC3200 DDRAM modules into older mobo and will work ok??

Yes.

Suppose you have an older mobo that supports DDR to a maximum speed of 333MHz. Also let's suppose you have 3 DIMM slots on that mobo, and that currently 1 of the slots is filled with a single 256MB stick of DDR333 RAM.

You can simply purchase and install a stick of PC3200 RAM. That RAM is rated for a maximum speed of 400MHz, but in that mobo it will be clocked at 333MHz, just like the existing module, because it's the maximum speed supported by the mobo. DDR is designed to support these lower speeds (i.e. downwardly compatible).

For example, a couple of weeks ago I upgraded 3 older Dells that support only 266MHz FSB. Each of them had only 256MB of 266MHz DDRAM. I added a single 512MB stick of PC3200 DDRAM to each. In those motherboards, the new RAM is being clocked at only 266MHz but it works just fine. Each machine works reliably and reports 768MB total RAM, as you'd expect.

If for some reason the machine won't boot after adding PC3200 DDRAM, the mobo may require a BIOS update. Remove the new RAM (leaving just the old), flash with the new BIOS and then reinstall the new RAM. Chances are you shouldn't have to do this unless your mobo is known to be buggy or is maybe one of the very earliest ones to support DDR.