I'm sure I read somewhere that in 2009 google's servers had only 16GB RAM each (but in 2005 they had an estimated 200,000 of them). Saying that I
have seen systems with a lot more than that but that's down to the motherboard having a LOAD of RAM slots, with each slot containing 2-4gig. I personally haven't seen a stick of RAM bigger than 4GB, though there may be as I haven't really been looking.
However...the NASA supercomputers (for example) have unbelieveable amounts of RAM. Here:
http://www.nas.nasa....s/columbia.html -
9 terabytes of RAM!!! (NOTE: I
think this is actually just a cluster of many; many; many systems).
EDIT
Heres a couple of links:
http://www.google.co...ed=0CC4Q8wIwAw#
http://cgi.ebay.co.u...1082149#vi-desc