Ever since switching to Slackware64 14.0 and KDE 4.8.5 I've been experiencing an issue where the KDE session gets more and more sluggish the longer I keep the session going. Switching from desktop to desktop via the pager gets increasingly sluggish, but is not the case on a fresh KDE session. Things also seem to get worse after running VMWare for a bit and the only way to remedy this is to restart KDE. This is on a system with 16GB of RAM with little to no swap usage.. Anyone have any suggestions?

Does toggling Desktop Effects have any impact here? You can press Alt + Shift + F12 to quickly toggle effects on and off.
I suspect your system might be running out of graphics memory, which might explain the slowness.

I remember trying this before, but I'll verify it again. It definitely does feel like this is the case... Is there any way to check how much graphics memory I have available, how much is in use, and what's using it?

Tried toggling Desktop Effects and it does not look to result in much of a difference.

Checking the use of graphics memory tends to be manufacturer / driver dependent i'm afraid. I do recall historical versions of the Nvidia driver did leak graphics memory, which could lead to various forms of slowdowns within KDE.

Ok so I'm experiencing this slowdown right now and according to nVidia's tool, I have 2048MB of total memory and 2048MB of dedicated memory. Currently 1078MB (53%) of dedicated memory in use... so hardware wise it should be fine no?

The memory usage should be fine in that case - are you using the latest version of the driver?
Also, have you tried using another media player? I did encounter one file once where VLC was very slow/jerky with playback, while GStreamer played it flawlessly.

I have been switching to the latest nVidia drivers of the Latest Short Lived Branch every time there's a new release and as far as I can remember using this line of versions I have had this issue. Unfortunately it may have been coincidental that it occurred around the same time that I switched to a newer version of KDE. To reiterate my issue, it's not with playing video that's sluggish, it's more with switching between desktops. The current number of desktops I have is 8 and when these slowdowns occur it can take 2-3 seconds to display a desktop when switching from another instead of the quick no lag switching I get when I start a fresh KDE session.

Anyhow I have temporarily switched nVidia drivers to the Latest Long Lived Branch version and so far after about a 17 hours with VMWare running, KDE is still snappy. I'll stay in KDE as long as possible and report back after some more time has passed. If you have further suggestions, please do list them.

You could try looking into the various pixmap commands which one did have to use with the Nvidia drivers at one point to ensure performance was retained under KDE. They may help in this situation.

It appears you are suffering from the affects of a regression in the Nvidia drivers, so you may want to report that to Nvidia so they can investigate.

Well, after a few days of testing and examining I believe this issue has more to do with KDE than anything else. After about a day or so in KDE 4.10.3 I see X using triple the amount of memory compared to what I start off with and it never goes down. At first I thought it may have been VMWare causing this, but I've had this issue even without any VMWare sessions running. Then I thought it was the video drivers and perhaps maybe even X itself so the easiest way to verify these two, as well as any apps that could be part of my daily routine I switched desktop environments. I've been using Xfce for the past 2 days and X's memory usage has remained fairly constant compared to the beginning of my Xfce session and I am experiencing absolutely no change in performance as well. I would have to say that it is a fair assessment that as my KDE session grew more and more sluggish, X's memory usage also grew more and more. On top of this, CPU usage for X would also spike 3x above normal. I'm not sure how one would resolve this or even file for bug reporting since it looks like I'm the only one experiencing this with no specifics of where the issue is stemming from... if you or anyone has any suggestions I'd be willing to hear them.

Does xrestop indicate any particular application is using memory excessively?

One thing you could do is try restarting KWin and Plasma Desktop, as both are very long running and graphics intensive. Pixmap leaks have been reported in Plasma before.

As far as I can tell, the only thing using up the majority of the memory reported by xrestop is "anon". Whatever this is, it's like a blackhole for memory as it only increases and never decreases. I have tried restarting KWin and Plasma Desktop during these performance hits, but it only seems to resolve it for a few minutes ever so slightly before resuming where it had left off with the sluggishness.

Okay, the "anon" entry indicates that there is probably a memory leak occurring in X itself, or the drivers you are using. Given that KWin and Plasma Desktop are the two major graphics users in KDE, there aren't other applications I can think of which could be at fault here.

There is not much you can do about this unfortunately from what I can tell, other than logout and back in again when it gets too high.
You are probably hitting a interaction between KDE, X and the Nvidia drivers, which would explain why this does not occur under Xfce.

That's a little disappointing, but it was also the biggest fear I had. Perhaps if I get some time I'll switch to the nouveau drivers and see if I can at least narrow down where the leak is coming from. Thanks for your help bcooksley!

We may have the same issue. viewtopic.php?f=67&t=110294

i alleviated my problem by disabling xchat tray icon & using dropbox sparingly. I only use it at startup to update files for 2-4mins and I quit the application. If you have any other gtk apps that use tray icons, disable the tray icon or use them sparingly.