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Fight the lag!

I read somewhere that lag is like rain, you must accept it as an inherent reality in Second Life. But lag, if unavoidable, can be greatly reduced. Most of the case I examined could be brought down to 3 types of lagging, and 90% of those problems were on the client side. To resume there is 3 types of lagging:

  • Client lag (you are lagging)
  • Netlag (the network between you and SL servers is too slow or congestionned)
  • Simlag (your sim is full of campers, ugly malls and laggy scripts)

Most of the severe cases are netlag and client lag, so I will tackle them first.

Client lag

  • RAM: It’s all about the RAM baby! You have 512 megs? It’s not enough. Second Life often memory leaks and I have seen it eat over 1,5Gigs of RAM! I ugraded to 768 and it was already much better than 512, but far from ideal. Codie recommends 2 Gigs. Why is it so important? At the second you reach your maximum physical memory, SL will start writing to the swap or virtual memory. Virtual RAM is hundreds of times slower than any physical RAM. As soon as it hits the spot, prepare for massive uber-lag. Symptoms are the machine starting to write long bursts of data to the hard disk, everything slowing down to an almost halt, and occasional crashes. This is the #1 cause for heavy lag among SL users.
  • Defrag it: Yes fragmented hard disk will cause some lag for every applications. So do it often. Also be wise and separate your data from your OS with partitions. This will ensure less severe fragmentation.
  • Disk space left: Go below 10% of your total first partition space and watch your machine crawl. Example if you have a 40 Gigs harddrive and there’s 2 Gigs left, good luck. The lower you go, the slower it will crawl.
  • Shitty Videocard: Yes SL works with ATI and some Intel video chipsets. But the performance is less than glamorous. If you plan to buy a machine to play SL, go Nvidia and avoid a lot of troubles.
  • There are other possible causes for client-side lag, I will add up more when I think about it

Netlag

The second most frequent cause for massive lag is network congestion. It affects a lot of Euro SL players, especially those in countries with bad network repartition. But mainly, ignorance of the users about their actual network speed and bandwidth sharing is the leading cause for frustration. Here is a troubleshooting checklist:

  1. Shutdown all heavyweight network suckerage applications, mainly P2P apps like Bittorrent.
  2. Open a web browser and go on http://speakeasy.net
  3. Choose San Francisco, the location of Linden Labs datacenters
  4. Wait for the test results
  5. You will get a download speed in kilobits-per-second (kbps)
  6. If this speed is below 1000kbps (1mbps) your connection can be classified as SLOW and requires special settings
  7. If this speed is above, make sure that SL is configured to use maximum avaliable bandwidth

Once your maximum speed is determined, you need to check if SL is adapted for that speed. Go to Preferences > Network and check for the Maximum Bandwitdh slider. If your connection is SLOW (ex. 500kbps) you need to ajust the slider LOWER than the mentioned speed. If the connection is faster than 1000kbps, make sure it’s cranked to the max. This way you will insure that the avaliable bandwidth doesnt affect your SLclient and create bottlenecks. If your speed settings are higher than your actual speed, this will cause massive lag, because the SL client will request more objects to the servers than it is able to handle.

Simlag

Simlag is dreadful because apart good neighborhood and civic sense, nothing can prevent it. It is caused mainly by overcrowded areas (clubs, campers, or just too much people), laggy scripts (too many listen events, badly written loops, abuse of particle effects, etc…), and other sim packing activities. You will remark the effect in crowded places, casinos, clubs, shopping malls and so on.

The problem is less of one when it’s happening on private sims since it doesn’t affect the average resident. It becomes more of a problem when casinos, high traffic clubs and malls appears on Mainland parcels, since other residents also pays for the right to enjoy their places, and when single small parcel owners for casinos for example, sucks massive resources on the sim but are still in fact small residents. When this is the case one resident can impact on all the simulator and cause massive lag to the other residents.

Since SL simulators are nothing but Apache web servers, the principle is the same of virtual shared hosting. If one customer on your machine runs scripts 24/24 and have 40 people on their website permanently, chances are this will greatly affect your other customers. Personally in my day to day business, I isolate those customers and offer them a dedicated server. Linden Labs does little to control this aspect, let’s say I understand them because it can be a headache to do so, but IMOHO any Mainland resident that sucks so much ressources on a sim to render this sim unusable should pay for it’s own sim, unless of course the resident owns a vast majority of the sim.

Anyways, Mygdala and her friends are on a fight against lag with the Lag Annihilation Group, you can find information and nice posters on her blog.