Mac mini ethernet speeds not gigabit? I've been writing a script for my Mac Mini (2014) that does a speed test and logs the data to a database. All that works great, but the results were a lot lower than I was expecting.

I have a gigabit connection and my Mac Mini is hardwired directly to my Airport Extreme. I was expecting to see something around 900 Mbps, but it was more like 500 Mbps. I would usually blame my ISP at this point, but I decided to run the test from my Macbook Pro as well. My laptop was spitting out in the upper 900s consistently. My setup between my Mac Mini and my Macbook Pro are identical, both hardwired (with the same cable) to my Airport Extreme.

I looked up the specs for my Mac Mini and it says that it's 10/100/1000BASE-T
https://support.apple.com/kb/sp710?locale=en_US

I'm confused, why am I getting such drastically different results?
Mac minis ship with 5400 RPM spinning hard drives. Even if you’re using a Fusion Drive configuration, its solid state portion is likely taken up by more-frequently accessed files.

So assuming your downloaded data gets written to some temporary file, your benchmark is running off the mechanical drive. Add to that the overhead of recording logs to a separate database, which will further decrease your storage performance.

On the other hand, Apple laptops all ship with SSDs. An SSD should easily keep up with a Gbps connection.

The most probable scenario is your Mac mini is being bottlenecked by its hard drive.