Read Speed 50% Slower Than Expected

Question

have an issue with our internal network that I’ve been trying to troubleshoot for the past two days with no luck, wondering if I can get any answers or ideas that we haven’t thought of yet.

We have a server computer running Mac OS10.7 and using a SmallTree Six Port GbE (RJ45) - P2ED-6-T to connect six clients via ethernet to our server drive connected via eSATA.

Each client is running Mac OS10.9.5 and has two drives, an HDD (for file storage and backup) and a SSD (for running software and applications).

Here is the issue:

When we test the read/write speed via Blackmagic Disk Speed Test on the server from the client we get write speeds of about 115MB/s and read speeds of around 35MB/s. Realistically it seems like we should be seeing about 90MB/s for both the read and write speeds.

After troubleshooting this for a while, I did some timed tests transferring a 4.7GB file.

When we transferred from the SSD on the client to the server, it finished in about 0min 35sec. When we transferred from the server to the SSD on the client, we got 3min 30sec.

When we transferred from the HDD on the client to the server, it finished in about 0min 35sec. When we transferred from the server to the HDD on the client we got 0min 45sec.

I tested this multiple times so these times are averages of a couple tests.

To add to the confusion, if we connect a Macbook Pro using an i7 processor on the network, the speeds even out to what we’d expect, about 85-90MB/s read and write. The other clients are Mac Pros with Xeon processors.

Any ideas? I can garner more information if needed.