Unable to get two 512Mb ram banks working together
 

Hi all,
this is really getting me a nasty headhache. I am not a hardware expert and none of those "experts" in computer shops could help (being merely win hd formatters...)
I recently bought a second 512Mb ram bank (Vdata DDR400 512*16) identic to the one I already have on my motherboard.
Now the problem is that the PC just freezes or panic kernel when the second bank is added. I thought that the new bank was faulty so I managed to get a new identic one from the shop.
As matter of fact the pc keeps on paniking at boot or during a X session all of a sudden and apparently with no reason.
I tried to remove the old bank leaving on just the new one.... the pc worked perfectly for days without hitches. I tried all the positions in the ram mb sockets both with the old and the new 512Mb bank but with the same results.... 1 bank OK whereas 2 banks freeze the PC.
Could someone please give me some advice?
Thanks,
Pier

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