I had one leak. Water was running from CPU block-hose connection. It costs life of my gf3 (I gave it to warranty (one week before its ends) and they gave me Leadtek A310TD) - one mofset burned. I saw water just before going to school. All riva was wet, but it's still working.
now I'm running on alu cooler waiting for new blocks from
www.overcooled.com