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Is there anything else Maya stores that I can shut off?
No.
Setting item uses up 2-4*2 bytes of memory + the keyrame cache. which actually is a lot if you have thousands of objects. so every time you key frame a thousand objects you loose about 20 kilobytes of memory per range per object.
Its not important memory so maya does know how to swap it out effectively or even kill it if need be.
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if you could share how to set multiple key frame with unique key values that would be great!
make a function for it, that serves same purpose. but yes you can write the attribute arrays manually instead of using the key fame command.
It does not change the fact that underneath maya must set every piece of thing individually simply because computers have to do that. So fooling yourself into thinking maya does not do something does not mean it does not do so.