Performance - Ranking
It's worth noting again that the Performance Ranking takes into account only Gigabit Ethernet performance. For this review, I filtered for RAID5 class NASes and Revision 5 Test Method. The ASUSTOR AS7004T still retains #1 ranking based on performance. QNAP still holds on to rankings 2 through 4, with the Synology DS2015xs landing at number 5.
NAS Ranker filtered for RAID5 and Test Method Revision 5 showing Total NAS ranking
The composite chart below shows detailed performance for the Synology DS2015xs and QNAP TVS-471-i3-4G. The QNAP TVS-471 had category wins for Write Benchmarks, Read Benchmarks, Mixed Read Write and iSCSI. Based on the individual benchmark tests above, it's no surprise that the DS2015 had higher category scores for Video and Backup. QNAP's backup category score was dragged down by the relatively slow Rsync backup.
Ranker performance comparison for the Synology DS2015xs and QNAP TVS-471-i3-4G
If you are in the market for an eight bay NAS, the options available start to dwindle compared to four bay NASes. By choosing the Annapurna Labs AL-514 SOC with built-in 10 GbE support, Synology's DS2015xs has carved out its own market niche as an eight bay NAS with built-in dual SFP+ 10GbE ports for a very impressive $1400.
But that price does not include some features found in its competition, specifically, an LCD panel and PCIe expansion, eSATA and HDMI ports.
So just how much of a value is the DS2105xs? Competing for your eight-bay NAS dollars is the eight bay version of the ASUSTOR AS7004T - the AS7008T. On Amazon, the AS7008T averages $1855, and that's without the optional $499 10GbE dual SFP+ expansion ports. Similarly the eight-port version of the reviewed QNAP TVS-471, the TVS-871 sells for $1449, without the optional $429 dual port 10GBASE-T expansion card.
If you can live with the compromises outlined above, the DS2015xs is hands down the best value for an eight bay NAS - even if you don't intend to use 10GbE. If you do intend to use 10GbE, the value proposition only gets better because of the included dual SFP+ 10 GbE ports.
Your final decision might come down to how you intend to use the massive amount of storage potential offered by an eight-bay NAS. If iSCSI via 10GbE is your focus, you might want to pass on the DS2015xs. The chart below shows the DS2015xs ranked last for 10GbE iSCSI both for Write and Read by a significant margin.