God I'm sorry to keep going on this should be my last post - just want all his written down for future victims to find when searching in the middle of the night.
Think the '0' is a 'D' in my part number, TC50 will always mean 5ns anyway but this site lists memory and is useful ;
http://www.techpowerup.com/articles/...ng/vidcard/106
Samsung K4D551638D-TC2A 256 MBit 'D' die 2.8 ns TSOP-II 66
Samsung K4D551638D-TC33 256 MBit 'D' die 3.3 ns TSOP-II 66
Samsung K4D551638D-TC40 256 MBit 'D' die 4.0 ns TSOP-II 66
Samsung K4D551638D-TC50 256 MBit 'D' die 5.0 ns TSOP-II 66
Samsung K4D551638D-TC60 256 MBit 'D' die 6.0 ns TSOP-II 66
Samsung K4D551638F-TC50 256 MBit 'F' die 5.0 ns TSOP-II 66
Samsung K4D551638F-TC60 256 MBit 'F' die 6.0 ns TSOP-II 66
Thanks,
Geoff
Wellington, New Zealand.