I have an HP Pavilion ze5700 notebook with a whopping 256 MB RAM (and
onboard video)!

Yes, HP for some reason thought this was enough RAM to run Windows XP!

I'd like to add more RAM. I see no reason why I can't add 512 MB.

However, I'm a bit confused. Please compare these two modules:

http://www.crucial.com/store/mpartsp...52D384A5CA7304

and

http://www.crucial.com/store/mpartsp...EC39EBA5CA7304


Other than the $15 price difference, it's hard to see what else is
different. One is for a Pavilion and the other is for a Presario. But
the only other difference I see is that the Presario one says "64Meg X
64." What does that mean? Is there a real difference?