Re:Author doesn't mention his newbie status (Score 1)

Maximum throughput of a filesystem IS filesystem architecture dependant, and XFS solved that problem at it's time. Check your facts.

Also, imagine this - your filesystem uses some kind of block size, allocating a block requires round-trip through the filesystem (including touching superblocks and modifying list of free blocks).

What happens when you're trying to write a lot of data to such synchronous filesystem?

You're bound by round-trip time, no amount of faster hardware would help. Similiar situations used to happen at the time XFS was being designed.