I have a 2862ac

I have a virgin 1Gb connection to my house. I noticed that my speed test results were only around the 350Mb range. My Virgin (Hub5) was set to modem mode. In order for Virgin to test my speed we had to put it back to normal mode. I disconnected all my network devices, and the engineer from Virgin ran the test, which showed 980Mb speed.

I connected a laptop directly to the Virgin Hub5 and saw 980Mb also confirming the speed to the house was as it should be.

I then connected a LAN cable to the Hub5 that goes back to a patch panel in my network cab and tested again from the patch panel into my laptop and saw 970Mb when I ran the speed test. I then patched the feed from the Hub5 into my Netgear switch, connected my laptop to the switch, and tested again and still had speeds over 950Mb.

When I connected my 2862 back into the network (between the Hub5 and the switch) the speeds dropped to 350Mb. If I connected it directly to the Hub5 and nothing else, then connected my laptop to the Dray Tek and still saw speeds of 350Mb only, but if I moved the cable from the Hub to my laptop disconnecting the 2862 the speed was back up to 950Mb.

It appears the Dray Tek is throttling the speeds. Why should this be ?

Hardware acceleration enabled ?

See here

https://www.draytek.co.uk/support/guides/kb-hardware-acceleration-tips

and here for more details (as your 2862 is kind-of an in-between model with respect to what settings it requires to get full performance)

https://www.draytek.co.uk/our-solutions/videos/draytek-webinars/draytek-router-wan-performance-and-hardware-acceleration