If something becomes faster, we say this is an improvement in speed.
If something becomes lighter, we say this is an improvement in weight (assuming that a low weight is desirable).
If something becomes smaller, we say this is an improvement in size (assuming that smaller is better).
But how do we best describe, using an adjective, that there has been an improvement in storage capacity? That is, computer hardware has become more ____ (what, exactly?) "Capable" does not sound correct. I am looking for an adjective meaning "having capacity," such that the phrase
improvements in speed, size, weight, and storage capacity
could be replaced with
have become, smaller, faster, lighter, and __________ (new word here)
EDIT:
The difficulty here seems to be the context. I'm talking about computer hardware. The computers themselves have become smaller, but the storage capacities have become larger. If I say "computers have become more spacious" it sounds like the hardware takes up more space. There's something tricky about the container becoming smaller, but the internal storage elements becoming much denser. I don't know how to add a suffix or choose a word for this. "Memory denser" is not good English.