hi,
For that reason, using DRAM with a '51 is one of those 'exotic' applications that have no real value, but some do it just to prove that it can be done.

Well, using external chip either DRAM controller or PLD) may help alot. The reason is that DRAM is cheaper than SRAM. Using SIMM/DIMM you pay only about 10USD for 64Mb. Anyway I cannot imagine that such exotic configuration may be required.

Regards,
Oleg