Can I mix 266 and 400 DDR Memory?

I have two 512 meg DDR Memory Modules. They are both 512 meg as
mentioned and PC3200. The thing is the new one I just bought was a
400 (What does this number mean, is it speed)? and the other seems to
be a 266 going by the label on the module. I want to put these both in
a new system I'm building but I'm concerned if they will work
properly. Will it slow my system down or cause any reliability
problems? If so maybe I'm better off with just the 512meg 400 or
either upgrading the other to a 400.

On Wed, 17 Dec 2003 17:01:22 GMT, MarkW
<markwco(removenospam)@comcast.net> wrote:

 >I have two 512 meg DDR Memory Modules. They are both 512 meg as
 >mentioned and PC3200. The thing is the new one I just bought was a
 >400 (What does this number mean, is it speed)? and the other seems to
 >be a 266 going by the label on the module. I want to put these both in
 >a new system I'm building but I'm concerned if they will work
 >properly. Will it slow my system down or cause any reliability
 >problems? If so maybe I'm better off with just the 512meg 400 or
 >either upgrading the other to a 400.
I wanted to add this, if it is true that the 400 is faster but they
both work together would it help if I maybe put the 400 in the first
memory slot so that the system uses that first and not the 2nd module
as much?<!-- ~MESSAGE_AFTER~ -->