Hi
i was wondering if anyone can help i have currently have 2 gig of ddr2 pc 6400 ram in my pc and a friend has given me 512 mb of ddr2 4200, my understanding is that if i put the 512 stick in my pc my 2gig would only run at the slower speed but my friend claims he has read that this is no longer the case with ddr2.
Can anyone please tell me who is right
you help would be much apreciated
Your friend is wrong I’m afraid.
The memory would just run at the slower speed.
Using slower DDR2 memory in a system capable
of higher speeds results in the bus running at the
speed of the slowest memory in use.
For half a gig of RAM it’s not worth it. 
Here’s a Yahoo ink on the same question Click
And heres a site on memory with some utils for testing it out Crucial
Thanks for the advice i thought that was the case