Iteresting that you should find the ram maintaining ts contents for so long Craig,I have had problems with dram maintaining its contents for upto a minute after the refresh has stopped and the power removed I sspect that the normal leakage paths are send to a very high impedance state with the power removed,you can sometimes see the same effect if you quickly reboot a pc and you can see just for a split second that the video ram still has the screen from just before the shutdown as it restarts.