I think if either stick goes wrong again, i'll get a refund.
I got the replacement 1GB stick this morning, and now im back to 2GB again! I cant believe how much a difference it makes.
I only run them @ 2.6V at the moment as im not overclocking, in fact Im underclocking, as they are running @ 200/200.
Only thing I did was change them from 8-3-3-3 to 5-2-2-2 and its running great