Evidently many of our players do NOT know about this, so this is just going to be a link compilation. Credit goes to whoever made them. Questions MAY be answered by me, but I don't know too much.
I DON'T KNOW ANYTHING ABOUT VISTA. IF YOU HAVE VISTA: Ask somebody else who DOES. If thats too hard for you, go on google, and search accordingly:
"Nagle Algorithm Vista"
"Wireless Zero Configuration Vista"
"TCP Optimizer Vista" (I think its the same for Vista and XP for this one).
First check: DON'T BE ON WIRELESS. IT IS BAD. IF YOU CAN'T NOT BE ON WIRELESS, THIS MAY HELP YOU:
THIS WILL NOT DO ANYTHING IF YOU USE ANOTHER WIRELESS NETWORK FINDER. Only if you use windows standard one. If you use another wireless network finder, then you will find Wireless Zero Configuration to be off automatically, as it overrides the one built in Windows.
This basically disables windows wireless adapter continuously and annoyingly trying to find a new connection, and its resulting lag.
Start->Run->"services.msc".
You will see a large list of services. Most of them we will not be touching. In fact we will only touch one. Scroll down till you find "Wireless Zero Configuration" and stop it.
You're going to have to stop it everytime your computer starts up after you connect to your wireless network. You can NOT disable it because Wireless Zero Configuration is what your computer uses to find the wireless network, but once it finds it it just lags your computer. So you need it to find it, and then you have to stop it. If you disable it, you won't be able to find your wireless again until you turn it on.
Second check: Nagle Algorithm. Evidently Mabinogi is a demanding game, and actually lags from Nagle. I'm not going to explain Nagle too much, but lets just say it lags and you want it off.
https://www.youtube.com/watch?v=DQPY-wh9PbUDo it.
Third check: TCP Optimizer.
Read: Its a lot smarter than me.
http://www.speedguide.net/tcpoptimizer.phpDownload:
http://www.speedguide.net/downloads.phpUse accordingly using knowledge with what you have learned from the "Read" link. You probably shouldn't bother with the super advanced stuff, just setting optimal connection speed and MTU should be plenty for you.
WHEN USING TCPOPTIMIZER: Make sure you check "Modify All Network Adapters" or whatever the correct spelling happens to be.