For what its worth, I am currently using the ADC212-100 with an old 486-33 laptop with 16MB RAM, parallel-port interface, WIN95OSR2,
260MB HDD. (Sharp PC-8650)
I believe the ADC212/3 is basically the same thing, just not as fast or deep. I use mine for watching motors on robots and switching power supply startups, which take a very long record length to provide me useful information.
One restriction I have noted is when I take a substantial sample ( say, greater than 1000 readings ), there is a delay as the data transfers. Like a second or so.
If I take it up to the 32K sample/channel limit of the ADC212/100, I may have to wait several seconds for the data to transfer. I kinda expected that. Some of those files are slightly over 100K. My laplink software did not do any better on a file of that size over the parallel port. ( This limitation does not concern me that much, as it takes me much longer than that to view and think about the data I see ).
On the bench, I have been using a Pentium 133/WIN95OSR2/32MB RAM with very good results, but around the robot, I like running the whole setup ( laptop and digitizer) from a 12V battery to eliminate any ground loops that might contaminate my measurements.
On the faster machines, you get more of a live display. From what I have seen, it appears the point of diminishing returns seems to be around a 300MHz Pentium/WIN98.
Beyond that, it looks like the primary limitation is data transfer speed across the parallel bus.
I do take a little performance hit for using a 486, but for what I am doing, its all I need. But I also think this is also the bare minimum one can get away with.