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I have bought a tunnel service by using OpenVPN. For a year I've had 10 Mbps max upload/download speed but now I've bought an additional 20 Mbps making the available total bandwidth 30 Mbps for me.

On their homepage there are some controls available for me, for example to restart the tunnel. I've done that. It also says that the speed has indeed been upgraded to 30 Mbps on their page. I also got an email that said they have upgraded the speed.

However after I reboot my machine, and OpenVPN has started up and is running as usual, when I look at the Windows Task Manager (opens when pressing CTRL+SHIFT+ESC) in the "Networking" tab I still have a link speed of only 10 Mbps.

Two adapters are listed: Local Area Connection 4 (10 Mbps) and Local Area Connection 5 (100 Mbps). LAC5 is my "real" adapter, I have a 100 Mbps Internet connection if I don't use a tunnel. LAC3 is the virtual adapter used by OpenVPN. The problem is that it is still showing 10 Mbps even though I have upgraded to 30 Mbps.

How can I fix this?

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up vote 13 down vote accepted

Actually I just figured out that the "Link Speed" displayed in the Task Manager (10 Mbps) is just a dummy number set by the driver that OpenVPN is using. It doesn't slow down the connection of the tunnel, even though my Local Area Connection 4 is maxed out on 100% of the available bandwidth for that adapter (10 Mbps) the Local Area Connection 5 can display that for example 25 Mbps is being used. So the "link speed" doesn't actually affect the transfer speeds at all and is just an eyesore.

I figured it out by first reading and then doing some tests to confirm that it was indeed like this. Here's two key quotes from the above forum link in case it 404s:

"the tap-win32 adapter will report that it is a 10 Mbps device but in theory it can support speeds up to ~ 160 Mbps . In practice speeds will top off at about 90 Mbps on Windows , but this has nothing to do with the speed reported by the adapter itself."
"the speed of the tap-win32 adapter is a bogus number - in order to change it you need to recompile the driver. I don't know of any plans of bumping up this bogus number; 10 Mbps is consistent with the linux tun/tap driver - it also reports 10 Mbps"

So unless someone posts something here that points to that the link speed actually DOES matter (and that my tests must have just been lucky or something) I'll take this as the answer to my own question:

There is no "fix" available, but it is also not needed; the link speed does not actually reflect the performance of the OpenVPN tunnel. The transfer speeds can go over that which is listed as "link speed" in the task manager.

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um ... while such a bogus number may not affect the actual performance since the driver stack receives packets once they're accepted and forwarded by the kernel it still may create (compensated) calculation errors within the internal hardware table - network adapters which transmit more than the propagated linkspeed attribute may very well be flagged as faulty / not fully WDF/WDM-compliant. This is a very bad design choice, its basically yet another windows application (or driver for that matter) which doesnt behave like microsoft intends it to - and this always leads to problems. – specializt Apr 28 '15 at 20:45

It might have to do with your router and its cpu, if the router acts as the OpenVPN client. If that's the case (router capped at 10 Mbps) the you will need a stronger device like the following D-Link Wireless Gigabit router

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