I love the Slide Show screensaver and the fact that I can tell it what folder to use for images, but I'm noticing that some of the transitions can take quite a while to paint the new image. This morning I stepped outside to enjoy a cigarette and locked the screen so my screensaver would activate but what I got back to my laptop the initial image was still being painted and the apps open on my desktop were still mostly visible. I don't know what the particular transition effect is called but it paints the new image in kind of jagged columns across the screen, never going more than say 50-100 pixels long at a time (I'm guessing here). I'm running LMDE with KDE 4.8.3 from the kde-qt repos.

This should not occur. What graphics card does your system have?

Also, what options do you have enabled in the slideshow configuration?

My Lenovo T61 has an Nvidia Quadro NVS 140M/PCIe/SSE2 (according to KInfocenter). My screensaver settings are

• Resize Images
• Random Order
• Show names
• 30 second delay
• My image folder is a folder with syslinks to my two primary wallpaper image folders, with subfolders on
• Start automatically after 5 minutes
• Require password after 90 seconds
• No widgets on screen saver but that's because I couldn't resize the analog clock plasmoid

As of right now Dolphin shows 974 images in 49 sub-folders between the two primary wallpaper folders. I did notice that if I tried to get a file count from my catchall folder it shows 0 images in 2 sub-folders, could it be part of my issue that I'm using system links within a folder rather than actual folders themselves? I have two main wallpaper folders because I use Webilder (in a Mint 12 KDE virtual machine) to grab new wallpaper images every day.

Does the performance change if you untick "Resize images"?
Also, would it be possible for you to record how busy the system CPU (and possibly GPU) is when the screensaver is active?

If CPU load is low, I suspect the graphics driver may be involved here.

In initial testing unckecking that box did speed things up, and I didn't need it checked anyway since I have a policy of resizing all of my wallpaper images to fit my screen anyway. This early in the day I don't have much running yet so I'll see how performance is as the day progresses, plus I'll try to note the CPU load if things start to slow down much.

I'd still like to be able to disable some of the transparencies though. Some of them, like the random painting of individual pixels until the entire image is revealed, just aren't my cup of espresso. I'd be willing to build a custom version of the code without them if that's possible.

Nice. The information concerning the CPU/GPU will be fairly important to diagnosing it further.

I've already noticed that when the screensaver seems to slow down my System Load Viewer bars for my two CPUs seem to be trying to peg the meter. What's the best way to get numbers for the CPU and GPU when the screensaver seems to get bogged down? I want to try to make sure I'm getting accurate numbers but I'm not sure what the proper ways to get them are.

Given this behaviour, it seems very likely that this is a CPU related matter - likely in regards to the display of the images.
If you open the folder of images in an application such as Gwenview does it handle them properly and display them at a proper speed (even when full-screen)?

That's actually harder to triage than it seems bcooksley. I probably have an odd configuration in that I have a "rotation" that I use for my screensaver images, rather like a radio station's "rotation" of songs they play. My images are spread across over 65 folders, some empty many not, so it's hard to fire up Gwenview and run that check. It does seem like an issue in how my dual-core CPU is used and am willing to call the issue of screensaver lag when my CPU are busy closed.

I am still wondering if there's a way to disable selected transition effects though. My OP mentioned the effect where individual pixels are painted in a random order until either the entire image is shown or the screensaver engine decides it's time to show a new image. I'm really not a fan of that transition, especially since if I unlock my screen with that transition being used I have to wait for the current group of pixels to be painted, which sometimes can take some time even if my CPU isn't pegged. Is there a way to either disable some transition methods or rebuild the code without some transitions? I love how KDE lets me configure so many things but I'm surprised that there's no way to select which transitions to use for the slide show screensaver.

This is definitely a bug of some description. I just tested locally - and while the preview appears to operate as I would expect, the full screen display does not.

As a quick guess, does disabling Desktop Effects have any impacts?

Disabling the effects definitely sped up the rendering of the images until I fired up Amarok (with a podcast collection update) VirtualBox and put a maximum load on my system. I guess it's time to go through my effects and see if I can tell which effects are pouring the molasses into my system.

Please update this thread when you find the offending Desktop Effect.

I experience similar problems. When I cancel the screensaver I can see (using a cpu widget) that one of the cores is at 100%. However, when I open a network folder with Gwenview all photos are rendered at acceptable speed.

Same problems here. Some of the transitions are quick, but others (the ones that paints dots, vertical lines... small things) repaint terribly slowly. I have Phenom II 4x 955 with 4Gb RAM and a Radeon 6850 graphic card with the free driver. All CPUs are about 50% of use (with other things opened, and 3 of the 4 CPUs are working at 800Mhz). Deactivating KDE effects or plasmoids on screensaver don't help. I think the problem is in the transitions itself. I would also like to select wich transitions to use.