How do I tell if partition alignment is my issue?

I have bveen trying to pin down a particularly frustrating issue I appear to be having with storage I/O.

I have read many articles documents about partition alignment, and the claims that fixing it could produce (up to) a 30% increase are definitely worth pursuing.

However, HOW DO I TELL if that's the core of my issue? What do I look for in any of my stats? I have spent a little time in esxtop, so I am not afraid to dig deep.

I'm just trying to save myself a little time before I go around trying to rebuild and re-architect the storage on these servers...

Thanks