[msellout]

Although we can theoretically handle up to 2^64 bytes of RAM (16 exabytes), the practical limit is much lower. I think someone on Wikipedia said it's somewhere around 8TB, but I imagine the performance of random access into 8TB RAM is much worse than a motherboard designed for up to 32GB RAM.

It's not as easy as just buying more RAM. You'll have to pay more attention to how you make use of the various caches in between your CPU and RAM.

[gambiting]

I imagine that on a motherboard with 96x RAM slots, the access time between the first one in row and the last one will be actually quite different, due to the physical distance between them.