when not connected, i get 400mbps. connected to mullvad, i only get 150mbps
the server isnt very far from me physically (sub 100miles) and says it can support 1gbps. any way to fix or is this just an inherent flaw with vpns? using wireguard
Very standard with any VPN, I'd say 150Mbps is quite good compared to the competition. You're sending your network traffic through a tunnel to another location, then they're relaying it to other places. There are several bottlenecks along the way.
Have you tried different servers (you can select country and city in the app)?
Have you tried it on different days of the week at different times?
That would be my starting to find out where the bottle-neck is. Under optimal conditions Mullvad should get very close to your 400mps (the protocol has some overhead, but in a speed test with "full" packages that's only about five percent of your bandwidth). Of course they can't guarantee optimal conditions on all servers all the time, but it's also not rare for them to get close.
The distance to the Mullvad server doesn't matter much when it comes to bandwidth. Hence, unless you're gaming and actually need a short ping, you can try servers that are further away.
If you don't get anything higher than 150Mb/s at any time with any server, we'll indeed have to look for technical issues on your side.
How much speed do you need? That is still a lot of bandwidth. This is from someone with 8 mbps up/ 60 mbps down. So your still way better then I am. I am envious. Well no so much as this is enough for me.
Other thing to keep in mind is that bandwidth is only half of performance, latency is the other. So check that too.
I don't know the limits of the mullvad client but you might want to look into split tunneling and just allow steam (or whatever program) to avoid the VPN... the privacy benefits are going to be marginal, the latency and download speed penalties will be blatantly obvious.
As dark ark say, the official mullvad app allows split tunneling. I have split tunneling enabled for things where I am logged in with my real identity. No point hiding my IP from steam when they have my credit card number with my name.