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Il Lag è la lentezza o il ritardo rispetto a quanto sarebbe desiderato con cui qualcosa avviene in Second Life. Può essere dovuto al server, al tuo computer, alla connessione internet, o agli oggetti, script e attività della zona in cui ti trovi o degli altri utenti attorno a te.

Il lag puo' manifestarsi nella scattosità e nelle difficoltà di movimento; nella lentezza di caricamento delle texture della zona in cui ci si trova; nelle chat, con lo stravolgimento dell'ordine dei messaggi, etc. Va di pari passo con il ritardo o la difficolta' da parte del programma nel rispondere ai comandi e con il calo di FPS (numero di fotogrammi al secondo).

Cause

Il lag ha diverse cause e a volte e' difficile capire quale sia il fattore che sta incidendo di piu' sulla propria esperienza di gioco.

Spesso le cause sono "lato utente": il client di Second Life consuma molte risorse e se non ve ne sono abbastanza a disposizione le prestazioni e la fluidita' del programma decresceranno inevitabilmente. Second Life è un'applicazione molto pesante che puo' mettere a dura prova il tuo computer. Scheda grafica, processore, disco fisso, memoria e collegamenti di rete saranno in grande attività quando usi Second Life. Le caratteristiche del proprio hardware e i driver utilizzati, nonche' lo stato della propria connessione internet possono essere i principali responsabili delle cattive prestazioni.

• consigli su alcuni settaggi per migliorare l'usabilità
• Ottimizzazione PC - programmi gratuiti
• Graphics Cards
• How to identify your graphics card
• Updating drivers

Lag dovuto al server

A volte e' necessario molto semplicemente abbandonare l'area in cui ci si trova, perche' puo' essere il server a essere sovraccarico e a causare il lag. Può essere dovuto alla presenza contemporanea di numerosi avatar, al numero e alla tipologia degli attachment che essi portano e all'esecuzione di troppi script, o script male progettati.

• Evitare il lag negli script LSL
• Come ridurre il lag sul simulatore
• il lag nelle costruzioni e nella gestione di una sim
• Quanto lag e' causato dal nostro avatar o da quelli degli altri?
• Windlight

Agire sulle Preferences per ridurre il lag

Alcune opzioni relative alla qualita' grafica possono causare molto lag se il proprio computer non e' sufficientemente potente. In questi casi puo' essere opportuno intervenire sulle Preferenze del client, ad esempio:

• diminuire la Draw Distance
• disabilitare la visualizzazione dei nomi degli avatar
• nascondere l'interfaccia (CTRL ALT F1)
• passare alla modalita' Mouselook
• rimpicciolire la finestra di Second Life
• passare a pieno schermo (Alt + Invio?)

Un buon procedimento per scegliere i giusti valori:
andare nelle Preferences / Graphics e spostare completamente a sinistra il cursore/slider Quality and Performances, poi contrassegnare la casella Custom e abbassare al minimo tutti i parametri grafici, per poi elevarli gradatamente uno alla volta, verificando come cambiano la resa grafica e le prestazioni del proprio computer. Controllare i FPS nelle statistiche (menu View / Statistics Bar - osservare il primo valore 'FPS' subito sotto la scritta Basic - cliccare su Basic se non vedete i FPS).

• molti consigli sono qui
• aprire la Statistics Bar (CTRL+SHIFT+1 o menu View) per vedere con precisione le prestazioni
• Usare l'opzione Avatar Rendering Cost che si trova nel menu Advanced / Rendering / Info displays per verificare quanto e' "pesante" un avatar dal punto di vista grafico

Open the Preferences window (Ctrl-P or Edit menu > Preference) and on the "Graphics" tab,

• Set the "Quality and Performance" slider to "Low"
• Check "Custom" checkbox.

Then,

• All checkboxes listed in the frame should be UNchecked.
• Set Draw Distance to 64 (very important, this is the biggest factor in video speed)
• Max Particle Count to 256 (the default is 4096, you can also disable particles temporarily with [Alt]+[Shift]+[=])
• Move "Mesh Detail" sliders all the way to the left
• Terrain Detail to "Low"
• Uncheck "Run Second Life in a window" (Top of the dialog)
• Set "Windows Size" lower, such as 800x600 or 1024x768

And push "Hardware Options" button. "Hardware Settings" dialog will appear, then,

• Check ON AGP Graphics Acceleration if you have the option
• Set "Antialiasing" to "Disabled"
• Uncheck "Enable VBO" checkbox. (Some machine may become unstable by checking this option.)
• Texture Memory Size should be set to small if you have 512MB of memory or less, or large if you have more.
• Fog Distance doesn't appear to have much of an effect, set it to your preference. (This option is enabled only when the "Basic Shaders" option on the previous dialog was unchecked. If the Basic Shaders option was checked, this Fog Distance will be determined by World menu > Environment Settings > Environment Editor > Advanced Sky button > Distance Multiplier.)

Following options may be obsolete:

• Set your video card memory size as low as possible (though you may want to turn it back up if everything seems too blurry to you)
• Check ON Avatar Vertex Program (turn this back off if you keep seeing avatars folded up into themselves)
• Bumpiness Draw Distance - set to 0 (it won't matter if Object Bump is off anyway)
• Outfit Composite Limit to 5 (no idea what this does, I think 5 is the default, and I don't see any differences in performance when changing it)

Additionally, it can help a lot to make sure you have the newest video drivers installed. If your drivers are more than a year old, chances are you will probably get some noticable improvement by upgrading them.

CPU

The CPU does a lot of work in SL compared to other applications. Everything that moves in the world has to be updated, and SL is a very dynamic world. SL will almost certainly run your CPU at full 100% utilization the entire time you have the program running. Due to the dynamic nature of SL, a CPU can often have more of an effect on improving your performance than a new video card.

Network

Your internet connection will also be used heavily, especially as you're flying around the world. Expect your bandwidth to idle at around 20-50 kilobits per second, and peak in the hundreds of kilobits per second while moving around or in a crowded area.

These are the three major sources of lag. CPU, Video, and Network. Often, when one is lagged, the others can appear to have lagged down as well. Here, I will try to give some advice on how to speed up each. Once you have eliminated all sources of lag, then you should go back and re-enable the options you are willing to compromise speed for.

Network

Bandwidth

In the upper right corner of your window, you should see two small vertical indicators. (If there aren't, hide search textbox from Edit menu > Preference > Genetal tab > Show search panel in overlay bar.) The one on the left is your PACKET LOSS, the one on the right is your CURRENT BANDWIDTH. These indicators can be green, yellow, or red, depending on the percentage.

Bandwidth is not as important of an indicator of lag as much as packet loss. If you see ANY indication of packet loss, that's not good. If you see it every once in a while, or in very busy areas with a lot of people, that is normal. But, if you're getting any significant amount of packet loss in quiet areas or while flying around, you may need to adjust your Bandwidth under your Preferences / Network tab. The exception to this is that some packet loss seems to occur regularly at busy hours.

1. Start with 300 kbps as your default.
2. If you're not experiencing any packet loss, but feel like the world is loading too slowly and your bandwidth indicator is often yellow or red, then raise your bandwidth higher.
3. If you are experiencing packet loss, reduce your bandwidth down until it stops.

Also, you may want to disable streaming audio (Preferences / Audio tab) if you do not have enough bandwidth or want to save some CPU cycles.

CPU/Memory

• Rebooting your computer before starting SL can help get better performance.
• Close as many background programs as you can while running SL, especially P2P programs
• Defragment your hard drive occasionally.
• SL works optimally with 1 GB of RAM (that's 1024 MB). More is better, but the payoff is much less beyond 1GB.

Tip: If you need to run background applications while running Second Life, you may want to try lowering the Task Priority for SecondLife.exe just a little bit to give those programs a chance to run a little more smoothly. Don't do this unless you absolutely have to, because it will slow down the SL client. I do this often when I'm browsing the web while running SL, as SL tends to eat up all of my CPU and makes my web browser very slow.

Additional Information

• To view your video and network status, press Alt+1
• Typical framerates are between 10-20 FPS in non-busy areas
• Typical network traffic is between 20-50 kbps in non-busy areas

Lag occurs most when

• Your Draw Distance is too high
• There are many physical (physics-enabled) objects nearby
• There is a large group of people nearby
• You are moving (and therefore loading new geometry, textures, and sounds)
• You or other people are playing sounds or animations
• When many objects are moving around nearby
• You have "fancy" graphics features enabled (Local Lighting, Object Bump, Ripple Water, Shadows, etc)

See Also

• Wikipedia: Lag
• Packet Loss
• related Knowledge Base articles:
  • SL Knowledge Base: I have a lot of lag. How can I improve performance?
  • SL Knowledge Base: How do I check for packet loss (network lag)?
  • SL Knowledge Base: How many avatars can I have on my region at once without causing serious problems with lag?
  • SL Knowledge Base: Typical Frame Rate Performance by Graphics Card/GPU

Link utili

• http://www.secondlifeitalia.com/community/viewtopic.php?t=2892
• http://www.secondlifeitalia.com/community/viewtopic.php?t=11410
• Links for Second Life Performance Tuning