My second computer gets double latency of my main computer, even when soloboxing.

[TheBigBB]

Mistakenly posted this in hardware first, but it belongs here.

Why would my new second Vista PC have double the latency of my main Mac Pro computer? Granted, the latency is typically in the 200ms range, but I get 90ms on average on the Mac. I tried changing my ethernet cord, and I've logged in one account at a time to test it. No matter what, I get double latency on the PC. It doesn't make anything worse to log into 5 accounts on the Vista PC versus logging into only one account. Inevitably all screens have twice the latency of all screens on the Mac when running 5 on one and 5 on the other.

Any ideas?

[Tynk]

Just randomly off the top of my head and without more information from your side like other network aware applications running on the two systems I would say, Vista is running a Virgin Network stack that has not been beaten into submission by hackers and the IT world in general while OSX is running a battle hardened stack that has been tweaked, polished, and buffed to a high sheen.

But before you make any assumptions, you should check a couple of things for running applications. Namely check what process are on each machine and run "netstat -a" and you will get a list of all network aware applications that are currently active.

When it all comes down to it though, two vastly different platforms with very different concepts of proper use of system resources, and 200ms latency is nothing to be concerned about.

[TheBigBB]

It actually shoots up to 300ms at times, very frequently. I'm messing around with my network settings hoping to notice something wrong or something running that shouldn't be.

[Freddie]

Windows turns the Nagle algorithm on by default. The Nagle algorithm results in times around 200 or even higher. It's done on purpose because it optimizes communications for many purposes, but it sucks for gaming. You can turn the Nagle algorithm off with a registry setting, or maybe it's two registry settings, I forget.

[Clanked]

Wasn't the Nagle Algorithm fixed in patch 2.3.2?

[Freddie]

Blizzard said they turned Nagle off in 2.3.2 but since then I've seen a number of forum posts saying WoW reverted the 2.3.2 change. I just Googled and found forum posts as recent as two months ago saying that disabling Nagle in the registry still helps.

Regardless of Nagle, Windows has a second registry setting, TcpAckFrequency, which may also help. The fastest setting is 1.

http://support.microsoft.com/kb/328890

[TheBigBB]

I think you're right about this, now I just need to figure out how to edit it out. I am not exactly a compute guru... by the way guys, I appreciate the help a lot!

[TheBigBB]

I did the following, but this didn't fix it:
The issue is something known as the "Nagle Algorithm". Anyways I'll keep it simple, this algorithm was created years ago as a way of allowing a steady stream of data to use low bandwidth. It was designed for older dial up modems to prevent online games and other things sending large numbers of small packets from filling up your entire bandwidth sending "ACK Packets". What this does is automatically delay your computer from responding to a single packet by 200ms which allows your computer to respond to multiple packets at once using less bandwidth. What this essentially does, is add up to 200ms to your lag. If you want to know more, do some googling; I don't want to bore you.
Anyways, if you are on a modern broadband connection, you can DRASTICALLY improve your Mabinogi lag by disabling this algorithm. I am unsure of how to do this in Windows Vista, but in Windows XP it is a simple registry edit.
1. Run Regedit
2. Browse to HKEY_LOCAL_MACHINE \SYSTEM\CurrentControlSet\Services\Tcpip\Parameter s\Interfaces\
3. It gets tricky here, there be a bunch of Folders with letters and numbers under this Key, you need to find the one that is your network adapter. Browse them one at a time and look for the ones with similar settings to your network, such as if you have an IP address or a Gateway manually set. If you are unsure, you could always just try adding the line to all of them.
4. Add a DWORD named TcpAckFrequency This is Case Sensitive. If it is already there, skip to step 5.
5. Set the Value of the DWORD to 1
6. Reboot your PC
After this, the Nagle Algorithm will be disabled.
If you wish to test your lag, the best way to do it is by casting the Healing spell. Try casting all 5 charges of your healing spell before this fix, then after. I guarantee you'll cast them twice as fast after this fix if you have had lag issues or are living on the east coast.

For more information read: http://smallvoid.com/article/winnt-nagle-algorithm.html
I was ready to quit this game due to lag issues until I found this. Now all of my problems have completely gone away. If this improves your game performance, please share!

[Freddie]

Glad to hear that setting TcpAckFrequency to one was helpful. However, that setting doesn't disable the Nagle Algorithm. It adjusts an optimization called Delayed Acks which interacts with Nagle but isn't the same as Nagle.

There's a lot of advice on forums saying you can disable the Nagle Algorithm globally by setting a different registry option, TCPNoDelay, to one. I always assumed this advice is true because there is a related option called TCP_NODELAY that applications programmers can use to turn off Nagle for their particular socket connections. For example, I use TCP_NODELAY in HotkeyNet to speed up HotkeyNet's transmissions when it sends commands to other copies of HotkeyNet. So it made sense that Microsoft would have a registry option with a similar name that does the same thing for all programs at once.

However a few minutes ago I looked up TCPNoDelay on Microsoft's website and read the documentation. The documentation says that TCPNoDelay sets Nagling for a Microsoft service called Microsoft Message Queuing. It's not clear whether that service affects all app's globally (including WoW) or only connections that make explict use of that service.

Microsoft articles about adjusting Delayed Acks with TcpAckFrequency:
http://support.microsoft.com/kb/328890
http://msdn.microsoft.com/en-us/library/aa505957.aspx

Microsoft article about disabling Nagle Algorithm with TCPNoDelay:
http://www.microsoft.com/technet/pro....mspx?mfr=true
http://technet.microsoft.com/en-us/l.../cc783904.aspx

[TheBigBB]

I played my healer on a separate box last night with this computer and my latency did drop to around 160ms at one point, which is better than I'd ever seen it, but something is still definitely up. I know most people would be fine with 150ms-300ms but no harm trying to improve it. I will look into this other setting!