several unique ways. Many of the settings can be changed by simply going to Tools > Preferences in Opera but some can only be used by accessing not so obvious ways like ini files.

Please note that everything that I’m describing here worked fine on my computer. It speed up Opera and increased my browsing experience with it tremendously. While most tips will work for any users no matter their connection to the Internet some tips might only increase performance for broadband users.

Disable Name Completion and local network lookup

Whenever you enter a single word into the address field Opera will look in your bookmarks for that name and try to find a local network with the name as well. Server Name Completion tries to append prefixes and suffixes to the name automatically. While this feature might be great for some users it uses time and cpu and should be turned of for faster browsing.

Click on Tools > Preferences, select the Advanced Tab and choose Network from the left menu. Click on Server Name Completion and disable Look for local network machine and try name completion, using.
Increase the time cached images are used before checking for new versions

Opera downloads images to its cache to be able to load them faster (from your hard drive) the next time you visit the website. By default Opera checks every 5 hours if a new version of that image has appeared on the website. If you increase this time you increase your overall performance.

Go to Tools > Preferences and click on the Advanced Tab. Choose History from the left menu and select Every 24 hours or even every week for image checks. You can always refresh the cache manually by typing F5 while visiting the website.
Remove unneeded and duplicate plugins

Type opera lugins in the address bar, this should display a list of plugins that are currently installed. Take a closer look and see if you find plugins that you never need. For instance if you never use Realplayer streams in Opera y
Another problem are duplicate plugins that are caused by loading the plugins from Firefox as well.This happens of course only if Firefox is installed on the same system.You can disable this easily by typing opera onfig in the address bar. Navigate to User Prefs > Plugin Path and delete the Firefox reference there.Rebuild your profile if you have upgraded Opera (a lot)
This is only for users who upgrade Opera a lot. I for instance was using Opera since version 6 and always upgraded from the old version to a new one.This could mess up the ini files, especially the opera6.ini file which is still used in all versions of Opera.This could lead to all sorts of problems (slow page loading, high cpu usage)caused by obsolete or incorrect entries in that ini file.The easiest approach would be to backup the file opera6.ini in your profiles folder of your Opera installation and delete it afterwards. Please note that Opera has to be closed before you do this. Restart Opera afterwards and it should automatically create a new opera6.ini file without all those old entries.You will loose the personal information if you entered them in Opera and also all tweaks that you might have applied are gone too. It is however not a big problem to enter them again using the Preferences for the personal information and about: config for the latter.Disable Turbo mode
While this might sound a little bit strange at first to disable turbo mode and present it as a tip to speed up Opera it becomes clear soon. Turbo mode means that Opera pre-draws any image which means that you see part of it although it is not fully loaded. This uses CPU and memory and could increase overall performance especially on slower computers. It should not be noticeable on fast computers though.
Type about onfig and enter Turbo into the search field. Disable Turbo Mode and click on save.Increase the number of total connections.If you happen to load many tabs at once and like to read websites more or less simultaneously you might want to increase the maximum number of connections.This should have a drastic impact on loading times if you use a broadband connection. It should not make a big difference for users with slow connections, such as 256K connections or less.Type about: config and enter connections into the search field. Change the value of Max Connections Total from 20 to another value,I suggest 32 or 64 connections. The Max Connections per Server setting should remain as it is.You might even want to test a lower setting, for instance 4 connections there.Reduce the amount of visited pages in history.Opera keeps track of the last 500 visited websites. The benefit is that Opera displays all urls that fit the string that you enter in the address bar. You can then scroll down and load the website without entering the url fully.This can however impact the time Opera needs to startup.
A temporary fix would be to clear the history manually, a better solution to reduce the amount of websites that Opera stores.
Click on Tools > Preferences and then on the advanced tab. Select History from the left menu and either click on Clear next to Addresses if you want to test if this solution really speeds up loading times or reduce the number of stored addresses in the history right away. I never use that feature and set it to 0. You might reduce it to 100 for instance.Change Expiry Settings.Some Webmasters want you to load their website anew every time you visit it to display new ad banners for instance. This has the effect that Opera will not use the files stored in cache to load the website but request the complete website again from the server increasing load times.We are however able to ignore the Expires meta tag from websites by changing two settings in the Opera configuration.Write opera onfig in the address bar, hit enter. Search for expiry and change the settings for Check Expiry History and Check Expiry Load to 1.Save Images Faster.This is probably more a usablity tip than a performance tip but I think it is still nice enough to be included. Instead of saving images by right-clicking on them and selecting Save Image you can simply press CTRL and left-click the image. The download window appears and you can save it then immediately.Delay mail and rss connections at startup.Opera prioritizes mail and rss accounts during startup. This could mean that you could witness lots of disk activity during startup which could slow down Opera significantly. It is possible to delay each account individually to prevent that Opera slows down during startup.Locate your accounts.ini file which should be in the Opera mail folder. Every account should have an entry Initial Poll Delay=X where X should be set to at least 60 (seconds) and the rss feed to something like 120 or more.
ya that's all