Mixing 6400 with 5400 ?

So far I got no answers to my thread here :
http://forums.hexus.net/showthread.php?t=96919

This forum is always busier so I hope my simple question can get a quick answer.

Can I have 5400 1GB old memory sitting in one bank with new added 6400 2GB sitting in another ?
Can it cause any probs if all is set to a reasonable speed, let's say 5400's nominal 667MHz ?
Both sets are effectively "matching" incl latencies ... (and the same price for 2GB of 6400 and 5400 !)
The only diff appears to be the nominal max speed.

Thanks and Regards

Robert

They should both run together but will be limited by the max speed of the slower ram.

you will also lose dual channel as well i would just run the 2gb set it is unlikely you would need more than that and the performance of the 2gb in dual channel would be better than 3gb in single channel at slower speed

Many thanks.

It all sounds sensible.

Regards

Robert