Draytek Vigor 2850 Speed Problem

Hi,
Not sure if this is the right forum but : -

I have a 80/20 mbps broadband connection. When I do a speed test, I consistently only get 45 mbps downstream. This is tested over several days.

The problem occurs if I use the Draytek as the modem, or if I use the BT Openreach as the modem, and the Draytek just as a router. The sync speed is fine (79812). And yes it is consistently fine, no dropouts. This has been confirmed by my ISP after days of monitoring.

If I swap the 2850 out for my cheapo TP-Link router, I get FULL speed (typically 75 mbps).... Again, consistently.

I've tried re-flashing the latest firmware and a full factory reset, but no difference.

I'm on the verge of shelling out for a new router, because this just does not make sense. How can my cheap router outperform my Draytek speed-wise?

Don't know if anyone has any experience of Draytek..

Thanks!
Mark.

There's one more test you should do. You can plug your computer directly into the Openreach modem and set up a PPPoE connection and test using that.

I think that's the first thing you need to do as this will eliminate the Draytek as a source of the problem. I'd be very surprised if the Draytek was limiting you as I've use the 2850 for several years on FTTC without any issues.

Who is your ISP?

wirerd or wireless?

Wired, cat 7.

My ISP is Zen Internet.

The thing to remember is, I've substituted another router *directly* in place of the Draytek. If the Openreach modem or line was at fault, the substitute router would also exhibit the problem.

The substitute router is a cheap TP-Link £35 router.... and the speed test sits beautifully at around 75mbps hardly wavering.

I'm at a loss. I generally know what I'm doing with all this; I've been a freelance software engineer for nearly 18 years, and I've written firmware in C for proprietary tracking devices (which was a challenge back in 2003!). Just trying to get across that generally when it comes to technical stuff and testing, I know what I'm doing.. I hope

But I still can't make a Draytek router work at full speed

any QOS, try a full factory reset; after testing the PPPoE connection with PC/MAC.

QoS all off, done factory reset several times and started from scratch.. no change

I may have found my answer.

Looking at the chart in the link below : -

http://www.draytek.co.uk/support/5

It seems to say the maximum NAT session throughput is 50Mb/s - assuming that is megabits and not megabytes...

Edited by deleted (Fri 05-Jan-18 08:49:11)

You omitted the link in your post ?

This has been a known bug for a while, that we have seen on 2850s for some time.

Basically from what I recall with ours and clients, it's something to do with QoS that limits the speeds, even when off. You need to enable it, increase the max throughput, save and then it should be ok. Even turning QoS at that point seems to maintain the throughput.

We reported this to Draytek 2 years ago, but they never seemed to be bothered to fix it. They released the 2860 less than 6 months after 2850 was launched.