As much as I love KDE4 and the KWin effects, I have to admit that it's performance does not compare well to Vista on my machine. I'm using plain old Intel Integrated graphics, so I don't expect anything fancy, but to my suprise, though the machine only scores a 3.5 on the Vista Experience scale, the Areo interface is very responsive. The visual effects are smooth, and the computer doesn't seem to take a major performance hit.

KDE4 is somewhat embarrassing in this respect; while the effects run okay, they are not very smooth; wobbly windows are very jerky, the desktop tends to skip while changing workspaces, and showing the dashboard causes the screen to flash white for second before suddenly displaying the dash (leaving the dashboard view is smoother). And I can often feel the performance of the machine degrade when the effects are enabled (and this is an Intel C2Quad@2.6Ghz!). It seems to me that KWin is using far too many resources, and not doing a good job with them. I know that I could expect a better video card to help out in this respect, but the question is, Vista doesn't have a problem with this machine, so why is KDE4's performance so poor in comparison?

Even some of the videos I've seen of the KWin wizardry (on what I assume to be far better machines than mine) seem rather jerky and unresponsive, though I suppose some of this could be attributed to the video quality and not to KWin.

I've made a few tweaks (thanks to some helpful characters on this forum) but the difference is still substantial. Does anyone else experience this?

Yes, I am experiencing it. The core problem is the drivers, which just aren't up to snuff. The proprietary drivers for Linux/Unix are second rate and buggy, and the open source drivers have only a few overworked developers and incomplete specs. I really don't know what video card/driver the Plasma/KWin developers are using, and I wish they would tell us. Maybe you need $500 quad-core GPU gaming cards.

One strange thing I've noticed is the "there is no problem" attitude among many users. They're so happy to get fancy effects that they're ignoring the poor performance and rendering artifacts. A couple of months ago I was mentioning some rendering problems to a friend of mine, who has the exact same laptop as mine. He said he had no problems at all. He sent me his xorg.conf, and it there was nothing in it that I didn't have as well. I asked to borrow his laptop, and it turned out he had exactly the same problems, he just thought it was normal behavior.

Like the flashies you used to get under 8-bit X11 displays. Many diehard Unixers pretended it was normal, but it sent Windows and Mac users screaming for the aspirin.

I tried to reproduce your problems with my computer (which gets 3.2 Windows 7 experience points BTW), but I can't reproduce them.
Well I won't lie to you the cube is not anti-aliased and the same goes for wobbly windows effect, but other than that everything is quite smooth on my
computer, which has GeForce 6600 card. Which according to google
costs from 50$ to 85$. But as you might know nVidia isn't the best choice for a GPU,
but with the new driver 188.22 it's quite good.
So maybe its time to go shopping

Primoz wrote:I tried to reproduce your problems with my computer (which gets 3.2 Windows 7 experience points BTW), but I can't reproduce them.
Well I won't lie to you the cube is not anti-aliased and the same goes for wobbly windows effect, but other than that everything is quite smooth on my
computer, which has GeForce 6600 card. Which according to google
costs from 50$ to 85$. But as you might know nVidia isn't the best choice for a GPU,
but with the new driver 188.22 it's quite good.
So maybe its time to go shopping

That's good to hear, and I may upgrade my card eventually (I really would like dual monitors) but my concern is not so much that the KWin effects on my machine are second rate, but that Vista's Areo performs better in comparison. I suppose the drivers are a big issue. These cards are designed for Windows, so little wonder Windows gets the most out of them. Ironic, though, because with most other hardware, one of the benefits of linux is increased utilization; that is, the same hardware can do more under linux than under Windows. Unfortunately it appears that graphics cards are an exception.

Like the flashes you used to get under 8-bit X11 displays.

Well, I suppose we can take comfort in the "used to" factor. Hopefully as open source drivers improve and hardware manufacturers become more cooperative, we'll see improvement.

Primoz wrote:So maybe its time to go shopping

I'm thinking about it, just because there are so many nVidia users that maybe one of them has the magic formula. But it's a closed proprietary driver. Surely there is a video card with an Open Source driver that works well with KDE4? Or am I being horribly naive?

Contrary to popular opinion nVidia produces the best and fastest drivers on Linux--ATI and Intel, although more open source, do not have anywhere near the best optimizations available in their drivers (They do have RandR 1.2 though which I guess does have its advantages). nVidia uses proper memory management techniques which prevent compositing managers from having to make workarounds and hacks, both of which have performance side effects. Hopefully development on DRI2 accelerates so that these memory management techniques can be brought to ATI and Intel systems ASAP.

I use a nVidia 7800GT. This is a four year old card that you can get second hand for between $30 and $50 and is nowhere near top-of-the-line these days. With this card I hardly ever go under 50fps while running a 3600x1200 desktop fully accelerated.

Those sorts of optimizations are nice and all, but I would much prefer if they instead focused on basic features like power management and randr support. As it stands now I am, like a great many people, getting a tiny fraction of my Nvidia card's full performance because it is locked in its lowest-power state. This means I cannot use desktop effects at all even though my card would be more than capable of running them if it wasn't crippling itself. This has been a well-known problem for years with Nvidia cards under Linux and there has been no progress whatsoever in resolving it.