All about Lag - EPG

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Lag/Ping

Enchanting Pony Girls

Stable and Training Center

Understanding lag

One of the biggest annoyance in Second Life is lag. Lag can seriously damage the user's Second Life experience. Especially a pony's experience during a run at a pony competition if catched by a huge lag spike five meters in front of the finish line after a perfect and faultless run.

Lag is a catch-all term to describe any kind of delay between what your brain expects to see vs. what you actually see. Lag occurs if something can't be processed as fast as it should and it feels noticeable slower than normal.

Second Life operates on a client server model like much of the internet. The "SIM" is the server, the internet is the network and our viewer runs on the client.

The actual source of the lag can be any of the above three components but the user perceives it as a worsening in expected performance. This can refer to delay between attempting to move vs. when your avatar actually moves, a delay in how often your screen draws the scene or even a delay in executing a script once you have clicked on your HUD or a menu button. In the worst case, your computer may just lock up and refuse to accept your inputs.

So when we talk about lag we have to distinguish between Server Sided Lag, Client Sided Lag and Network Lag.

How to reduce lag

Server Sided Lag

Note: Server sided lag affects all avatars on the SIM equally. Moving closer or further away from scripted/physics enabled objects/avatars will not have any effect on server lag.

There are two major causes:

Physics
People, even wearing nothing at all, with an Avatar Render Weight of 1, and no scripts, will lag a SIM. The SIM needs to keep track of where each avatar is, to prevent them walking through one another, floors, walls, etc. Avatar movement is VERY high when it comes to server side lag. Sitting down reduces this lag significantly. Your avatar, in fact, becomes linked to the prim you're sitting on.
Scripts
Scripts share the server's processing power and the available memory. So if there are too many scripts the server has too much to do and a backlog occurs. If the scripts are using too much memory it could happen that the server starts to cache data to a swap file, which also means a noticeable decrease in performance.

A few methods to reduce server sided lag:

1. Reduce scripts
2. Reduce scripts
3. Reduce scripts

How to do so:

Everybody

Detach all kind of scripted attachments you really don't need during the event before you TP to the sim (this also includes hud's, jewelry and whatever).

Hair mostly contains dozen or hundreds of resize and color change scripts and uses a huge amount of memory. Delete the resize scripts after setting the hair to the correct size. Most hair is copyable, so make a copy of the original one first and you are safe.
Also many clothes, shoes and attachments contains resize and/or color change scripts. Just the same, make a copy and then delete the scripts if you are done with the size and the color.
What if your object containing the scripts is 'no copy' but modifiable: just set the scripts in your objects to 'not running'. This way they will become inactive and will not use any CPU time (but still reserve some amount of memory). After the event - just set the scripts back to 'running'. To do so edit the object, go to the build menu and choose 'set scripts to not running' or 'set scripts to running'.

If the object is 'copy' it's better to make a copy and to remove the scripts then to set it to 'not running'. If scripts are set to 'not running' they are inactive and do not use any CPU time, but they still reserve the same amount of memory.
Use the built-in AO feature of your viewer instead of attaching your AO hud. The Firestorm viewer (and maybe other viewers too) has a built-in AO (Animation Overrider). This makes the use of scripted AOs unnecessary, which in turn reduces the amount of scripts you wear, and so server-side lag.

Spectators watching an event (this includes ponys not participating): Sit Down (sit on any kind of object or 'ground sit') and stay seated during the event. This does significantly reduce lag as the the server has not to perform physics calculation for the sitting avatars. Physics calculation is a heavy task for the server.

So in generall: if you buy new clothes, shoes or hair, also attachments like jewelry or whatever, check if there is a menu option to delete the scripts after setting up or check if it's modifyable the way you are able to delete the scripts manually. Prefere the copy versions - even if they are a bit more expensive - so you are save to delete the scripts after setting up. You're save with the original copy.

By the way. If you have a scripted object and would like to delete the scripts in it but can't because it's 'no mod' and does not provide a built in delete feature - owners of a private region are able to delete the scripts (using a tool provided to region owners). But make a copy before, as the scripts are destroyed after that and can not be repaired or set to 'running' again.

Sim Owner

In general SIM Owner should care about the CPU usage of all the scripted objects on the Sim. On a cultivated and decorated Sim there are thousands of scripted objects which can lag a Sim down. Think about if you really need this new heavy scripted tribune or if a self-made, unscripted one would be sufficient to seat the spectators. The same if you want to buy a new cart. Have a look at the numbers of scripts and the CPU usage. There are huge deviation. Choose one which is less scripted. This is also in regards of timer systems and the obstacles as part of your courses. This just as a few examples.

Linden Lab says an empty Sim - means no avatar on it - should not use more than 5 ms of CPU time to run smoothly. Most of the Sim's have a usage of 8 to 16 ms, or even more.

TP's

We all know almost every TP - in or out - ruins a pony's run. Bye the way, the less a Sim performs, the more lag is caused by a TP. So there is only one goal - to avoid TP's during a pony's run. Whenever possible a Sim should be locked for incoming TP's during an event. And of course - also outgoing TP's should be agreed with the event host.

Client Sided Lag

Note: Client sided lag is local to you and affects only you. The source of the lag is your PC. It is a direct result of how powerful your computer is. Client side lag has no impact on the sim's performance.

There are two major causes:

The Graphic Card
Everything you see has to be drawn by your graphics card. When there is too much to draw, when your computer cannot keep up, you experience client-side lag.
CPU and Memory
The Second Life Viewer program tends to use a lot of your computer resources. On a windows system, typing Ctrl-Alt-Del will open the "Windows Task Manager", whose performance tab can show you the current percentage utilization of your CPU. If you find out it is stuck at 100%, one option is to shut down any other programs you may have running. Another is to reduce the settings within the Viewer, or try an alternate viewer with lower requirements.
The program also uses several hundred MB of main memory. Once the real physical memory has been used up, most computers will swap data out to the hard drive temporarily. This is much slower. If you see the "Commit Charge" (actual memory used) is more than the amount of physical RAM installed in your computer, you have two options: shut down other programs and reduce settings in the SL Viewer, or add more memory to your computer.
As a guide, 512MB would be barely usable, 768MB is usable on the lowest settings, 1 GB is adequate, and more than that is good, especially if you want to run other programs at the same time.

Conclusion:

Your PC should have a modern CPU and a sufficient amount of memory (at least 2 GB) including a powerful graphic card.

Second Life is both graphics-intensive, and uses a lot of bandwidth to communicate with the Linden Lab servers. Therefore your computer must be capable enough in order to run the Viewer program with minimal problems.

Note: a SLI or Crossfire configuration with two or even more graphic cards does not increase the graphic power as Second Life is not designed to profit from a multi-GPU configuration.

A few methods to reduce client sided lag (in the order of importance):

Set your graphics to Low or Mid : Preferences → Graphics -> General → Quality and speed.
Reduce your draw distance ( do you really need to see 512m away? ).
Ensure that anisotropic filtering and anti-aliasing are both disabled in Preferences → Graphics → Hardware Settings tab.
Turn on avatar impostors in Preferences → Graphics -> General.
Disable atmospheric shaders in Preferences → Graphics -> General.
Deselect both "Render alpha masks" options in Preferences → Graphics → Rendering.
Turn off animated textures using Developer → Rendering → Animated Textures (CTRL+ALT+Q for Developer Menu).

Network Lag

Network lag occurs when there are problems somewhere in the network between your computer and the Linden Lab servers. Open up the statistics bar and look at the following :

Packet loss. Ideally this should be 0%. If it isn't you have a connectivity issue and are losing data
Ping SIM. Ideally, this should be under 200. Folks further away from the US may have naturally high ping times, and bye the way - conciderable disadvantage in competitive pony play.

A few methods to reduce network lag:

Some firewall software and anti virus programs are known to inhibit or interfere with a good connection.. You may want to temporarily disable them and see if the situation improves.
Video or music streaming, voice over IP, any downloads from the internet and other bandwidth intensive tasks compete for precious bandwidth resources. Shut down non-essential programs and check to see if your roommate / family is hogging the network all for themselves.
If ever possible use a wired connection. I you have to use wireless try to find out where you have the best connection quality.
Play with your bandwidth settings. A value to low, but even too high will result in network lag. For information on how to determine your optimal bandwidth, refer to this page.

References

Unfortunately, there is no one ultimate and up-to-date guide on Second Life Lag. Most of the existing documentation is maintained by the Second Life community. But many of blog entries on the topic were written years ago and have not been updated since. I have tried to gather the most important and up-to-date information.

But if you like to have a deeper dive into the topic or to find some additional or more detailed information, please take a look at the sites below: