You will find a complete explanation at:
http://www.pcforrest.freeserve.co.uk/resources.htm
It's too lengthy to include here, but he concludes:
"Therefore, no matter how much RAM you fit, you are always going to be
hindered by the 64K and 2MB "resource limits".
Most of the relevant iformation is in the first three- four paragraphs.
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What confuses me is that if, as others have said, system resources is a set
amount of RAM specifically for that, then the percentage of resources it
takes up should go down as the amount of RAM goes up.

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