In File-Server pattern there is a low percent of writes (20% to be exact), so the Seagate HDDs are going to feel quite confident in it.
Indeed, the Barracuda 7200.11 is far faster than the others whereas the Barracuda ES.2 is competing with the Hitachi drives, outperforming them under high load.
The next diagram shows detailed results for loads up to 32 requests.
You can see the Barracuda 7200.11 being slower than the Hitachi HDDs at a request queue depth of 1, but goes ahead at higher loads. The Barracuda ES.2 is competing with the Samsung at low loads.
The following diagram shows performance ratings of the HDDs calculated as the average of their results at loads of 1, 4, 16 and 64 requests.
So, the Barracuda 7200.11 delivers much higher performance than any other drive in this test whereas the Western Digital drive is the slowest here.