The interest of Gigabit
All of our tests were carried out in Gigabit ; however, does this interface really add a performance gain compared to Ethernet 10/100 Mbps ? To find out, we replaced our Gigabit switch by another 10/100 Mbps model and then re-launched our series of tests. We then obtained a clear answer to our question : yes, and without a doubt!
In 100 Mbps, the maximum theoretical speed is as high as 12.5 MB/s. This wasn’t entirely the case because the N5200BR Pro obtained 9.7 MB/s in writing just like the Qnap in reading.
The gain related to Gigabit then varies depending on the model and its performances : in writing from +21% (N4100+) to +220% (N5200BR Pro) which includes +49% (Synology) and +118% (Buffalo). In reading, of course the differences were even greater. If we put aside the N4100+ (+19%), the smallest gain was +112% (Buffalo)! This is followed by Synology (+187%), Qnap (+203%) and Thecus (+353%).
In short, given that the Gigabit is currently very widespread on motherboards, it’s entirely worth the money to invest in a switch of this type, for example, to replace the 10/100 Mbps plugs of your router.
Gigabit : the interest of jumbo frames
While looking at the advantages of the Gigabit network, we also wanted to see the advantage of jumbo frames because all of the NAS tested offer their support. What are jumbo frames? In an Ethernet network, files are not transmitted in blocks but rather cut up into standard size packets of 1500 bytes. The principle of jumbo frames is to user bigger packets in order to reduce the number of packets sent. For example, a packet of 9000 bytes equals six packets of 1500 bytes. This enables saving both processor power (less sending) and also in bandwidth because in the above example, because we only transmit a single Ethernet frame (therefore a single
header instead of six). This is only possible on a Gigabit network.
To benefit from this, of course the entire Ethernet chain must be configured with the same maximum size packets and obviously including the network cards as well as the switch. This is more and more the case, but not systematic. It’s all the more true that above 1500 bytes, packet sizes are not standardized at all. While the NAS tested here offer at least a size of 4 KB, with higher figures it is more variable:
– Thecus is limited to 7 KB on theN4100+ ;
– The N5200BR Pro offers sizes of 8, 12, and 16 KB ;
– Qnap and Buffalo propose 7 and 9 KB ;
– Synology features the whole range of sizes from 2 to 9 KB with increments of 1 KB.
We tested all the models in 4 KB then in 9 KB when possible, except for the N5200BR Pro which was in 8 KB. There was no result for the N4100+, because it systematically crashed a few minutes after the activation of jumbo frames.
It was with Qnap that jumbo frames gave the biggest advantage with gains from 20.8% and 23.1% in reading while Synology wasn’t unaffected with 7.7% and 18.6%. For Buffalo, on the other hand, results were strange. We sometimes noticed a drop in performances (9 KB in writing and 4 KB in reading), and sometimes a gain (+14.5% in reading/9 KB). Finally, for the Thecus N5200BR Pro, the use of jumbo frames resulted in an inexplicable drop in performances !
