Operating system distributions try to craft a one size fits all partition layout for their file systems. Distributions cannot know the details about how your hardware is configured or how you use your system though. Do you have more than one storage drive? If so, you might be able to get a performance benefit by putting the write-heavy partitions (var and swap for example) on a separate drive from the others that tend to be more read-intensive since most drives cannot read and write at the same time.