The following graph shows the NAS server's total performance rating, comparing it to other units. The comparison is pretty straightforward as the tested unit is shown as 100%, and every other unit is relative to it. Please note that I only measure the raw performance in the graph below, not each unit's functionality and available feature set.
Performance gets a nice boost, compared to the DS920+.
Most of you will find the following graph the most interesting as it shows how much the performance of the NAS will set you back. I looked the current USD price of each NAS up on Newegg and used it and all relative performance numbers to calculate the performance-per-dollar index. I search for the unit at other popular online shops (e.g., Amazon) if Newegg doesn't have the NAS in stock, and if the unit is not sold in the U.S., I search popular EU shops (e.g., Caseking), converting the price to US dollars. For discontinued NAS servers, I used the last selling price.
The high price doesn't allow for a good place in this chart.