Upgrading a Dell Dimension 8200?

I have a very old Dell Dimension 8200 desktop PC that I found at a yard sale for free, and initially it came with only 256 MB of RDRAM. I ordered a 1 GB kit for it, and the seller had shipped me 4 512 MB modules that fit in the PC just fine. That made the RAM go from 256 MB to 2 GB, though apparently the 8200 can supposedly only go up to 1 GB. Any reason why that was possible? Anyways, I will try and upgrade the CPU from 1.7 ghz over to something higher (gotta find the chipset it has) and if I have enough money, I'll put a better video card in it. And before anyone says to buy a new PC with the money it would take to put new parts in this; I have a very good, 2013 PC that works fine. I just want to see how far I can upgrade the 8200, just as a project more than anything. But honestly; Why did the 2 GB upgrade actually work if Dell states it can go only up to 1 GB? I also seen that the PC I use daily, an Inspiron 660, can utilize around 32 GB, though Dell says up to 8 GB, though they have sold the same model with around 16 GB. It's all confusing.