How cheap are they? I bought DDR 400 samsung infineon for 65$ 512mb stick 3 years ago. Make sure you don't get a DOA product. Very cheap ebay stuff can't be trusted unless it's really special. Usuallly, what you pay is what you get. I don't think there're any stability issue running at 400mhz if it's specified @400mhz. As long as you don't overclock, there's no difference between other brand of RAM.