Not all graphics cards are equal, but one would expect them to perform the same or close to the same on one operating system as they do on another. Unfortunately, the lack of cooperation from some graphics chip manufacturers and the slow development of some open source drivers have created an environment where every user’s experience may be different.

KDE has several settings that you can tweak to get better performance with desktop effects. Unfortunately, there is no solution that fixes all issues, and even two users with the same graphics chip manufacturer but different models may have dramatically different results. The intent of this guide is to help you understand the different settings and what they can do to help improve performance.

Enable Desktop Effects

Many current Linux distributions will enable desktop effects by default. If your distribution does but you still cannot get desktop effects working, you should first check the settings.

1. Open “System Settings” from the K-menu or press Alt+F2 and type “System Settings”.
2. Under Workspace Appearance and Behavior, click “Desktop Effects”.
3. Check the “Enable desktop effects” box.

If you cannot check the box and it tells you that it could not be enabled, KDE may have your graphics card on its black list. To get around this problem, you will need to manually edit ~/.kde/share/config/kwinrc. You can use the following commands from a terminal:

kwriteconfig -file kwinrc -group Compositing -key Enabled true
kwriteconfig -file kwinrc -group Compositing -key OpenGLIsUnsafe false
kwriteconfig -file kwinrc -group Compositing -key CheckIsSafe true

Advanced Configuration

The “Advanced” tab in the “Desktop Effects” configuration allows you to tweak your effect system to work better with your graphics card. As a warning, you should know that some settings may cause your screen to become unreadable or cause desktop effects to stop working. Fortunately, any changes you make will revert back to their previous settings if you are unable to confirm them.

Compositing type

There are two choices here: OpenGL (3D) and XRender (2D). From my experience, graphics cards with good 3D hardware and drivers should always use OpenGL. Nvidia and AMD cards usually fall into this category, although the AMD/ATI drivers may vary in performance depending on the age of your card. Recent Intel graphics drivers have been horrendous, and your 3D performance will probably be significantly lower than it would in Windows. Because of this, I recommend using XRender with Intel graphics chips until the drivers are improved. The down side of XRender is that it will disable some effects, such as Desktop Cube and Cover Switch. Most, however, such as Transparency, Shadows, and Desktop Grid, will continue to function.

If you want to make sure desktop effects stay enabled no matter what, check the “Disable functionality checks” box. This may help if some effects work with your card but are not supported.

Keep window thumbnails

In most situations, you can leave the setting “Only for Shown Windows”. If you experience any problems, you can always disable it.

Scale method

This is all about speed vs. quality, and only the discerning eye will know the difference. “Crisp” is faster and more rigid, while “Smooth” is slower and more polished.

If you think suspending desktop effects will improve performance, you can check “Suspend desktop effects for fullscreen windows”. This may help some games and videos.

OpenGL mode

There are three settings for OpenGL mode:

• Texture from Pixmap – In this setting, textures are stored directly in the graphics card’s memory, which is usually faster than storing them in the system memory
• Shared memory – This stores the textures in your X server’s shared memory, which is a section of your system memory. Use this only if pixmaps do not work, as it is usually slower.
• Fallback – This setting simply tries Texture from Pixmap and then switches to Shared memory if the former does not work.

Direct rendering

This is one setting that will vary greatly from one graphics card / driver combination to another. Generally, direct rendering should be faster as it bypasses X and sends instructions directly to the graphics card, but some cards have stability issues or incompatibility with this option.

VSync

With vertical synchronization, all screen drawing is synced with the monitor’s vertical display updates. It is designed to make the screen easier on the eyes and prevent tearing. For some, however, it can slow down performance.

The Right Combination

It is impossible to know what the perfect combination of settings will be without trying them on your own graphics card. Until the Linux graphic driver situation improves,  KDE users will have to do some tweaking to get optimal performance.

Related Posts:

• A Look at KDE Desktop Effects
• Preview of KDE 4.5
• How to Set Special Window Settings with KWin
• How to Check Your Gmail Account with Kmail

Though manufactured by different companies, GPU-Z from TechPowerUp does look a lot like the aforementioned CPU-Z. The interface is eerily similar and the name is a perfect match. On the positive side, these two Windows applications bring incredible value at a price that can’t be beat – free! The pair complement each other as incredible tools to have on your belt.

Let me take you on a tour of this powerful graphics card information utility.

Also in line with CPU-Z, this product doesn’t come with an installer. You simply download GPU-Z from the TechPowerUp website, save it to a folder and run it. At the time this article was published, the current version was 0.3.2

Vista users may experience a warning from the UAC security system, which asks if you are sure you want to run the file. No worries, click Run and wait for the application to load. You should see a splash screen while the information about your graphics card is collected.

Now the fun begins. The main window is divided into three tabs. There is the Graphics Card tab, the Sensors tab, and the Validation tab.

The Graphics Card tab is the default tab that loads when the application starts. It also contains the most information about your graphics card. Everything you ever wanted to know, and more, is displayed here.

As you can see in the image below, this tab tells you which graphics card you are using, the GPU, BIOS Version, Bus Interface, Memory Type and Size, Clock Frequencies, and much more. It has everything but the kitchen sink.

This information is great for anyone looking to upgrade their video card, or overclockers looking to get more performance out of their current setup. If you are running multiple video cards, the drop-down list at the bottom lets you select the card that you want to see the details for.

Moving right along in our tour, the next tab is the Sensors tab. There is no shocker here, this tab displays sensor data coming back from your video card.  Another great tool for overclockers, you can monitor things like Clock Speeds, GPU Temperature, PCB Temperature, and Fan Speeds.

There is also an option to log the data to a file and another to continue monitoring while GPU-Z is in the background. I like the last feature because it lets me monitor the change in my graphics card temperatures when I am in full screen gaming mode.

The last tab is labelled Validation, and it allows you to submit your information to the GPU-Z website. I couldn’t find any information as to the purpose of this feature, however it does let you share the details on the web and track changes to your graphics setup.

GPU-Z is another one of those lightweight, must-have tools that just about any user can make use of.  It really goes a long way to help you understand your graphics card.  You don’t have to take my word for it though, try it out for yourself!

Related Posts:

• Diagnose Your PC With CPU-Z
• Kill Problem Applications Like a Ninja
• Microsoft Pledges to Eliminate Pre-Packaged Bloatware With ‘Signature’
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