Copying a large file locally on the NAS using the WD Red 1TB hard drives saw the QNAP TS-435mini sustain 81.4MB/s while the Synology DS414slim managed 56.9MB/s making it 30% slower.
The QNAP TS-435mini was still incredibly fast in our game copy test when coupled with the 850 Pro, managing 91.2MB/s. Using the WD Red 1TB 2.5" hard drives almost halved that result with a throughput of 50.5MB/s. Once again the DS414slim was around 30% slower when comparing hard drive performance.
Using the WD Red 1TB 2.5" hard drives the QNAP TS-435mini was just 15% faster than the Synology DS414slim and 3x faster when using the 850 Pro SSD.