[SOLVED]Intel GMA4500M performing worse with Intel driver than default

Maruko · 2015-09-26 11:52:13

Hello,

I recently got myself a (somewhat old) Thinkpad T500 with an Intel GMA 4500M graphics chip. I use Gnome 3 as my desktop environment. After doing a fresh install, I noticed something interesting.

I forgot to install the xf86-video-intel package so X loads the glamoregl/fb driver by default. When I saw that, I installed the aforementioned package and my graphics performance suddenly dropped. The animations in Gnome are slightly jerky whereas they were perfectly smooth without the Intel driver. Also, scrolling in Chrome seemed smoother before. I tried switching the AccelMethod to uxa - no change. The only advantage I see is that there is no tearing in the animations anymore which was present with the default driver.

3D performance didn't change a lot. glxgears might have ~100fps more with the intel driver (score around 1600), but I have to check again.

Does anyone have a similar card and can reproduce this behavior? Is this normal? Is there any downside to using the default driver over the Intel one?

Thank you
Markus

Last edited by Maruko (2015-09-26 12:46:47)

Gusar · 2015-09-26 12:12:57

Nope, no downsides in using the default driver over xf86-video-intel. In fact, Fedora aims to at some point in the future use it exclusively for everything. What the intel driver offers are sna and uxa, but it's very much possible that there are scenarios where glamor works better. I think, but I have no numbers to back it up, sna would work better in a non-composited environment such as XFCE or LXDE. But Gnome is a very special beast. It's also GPU dependent, maybe sna on 4500M just isn't as optimized as on newer GPUs.

PS. glxgears is *not* a benchmark (I can't believe this still needs to be said nowadays). The 2d accel method shouldn't have any impact on actual 3d loads (glxgears isn't one of them) anyway.

Last edited by Gusar (2015-09-26 12:14:16)

Lone_Wolf · 2015-09-26 12:15:08

The glamoregl/fb driver used to be known as xf86-video-modesettting before it was integrated into xorg-server .
It uses a generic method to drive the card, while the intel driver tries to take advantage of card specific features.

In recent Xorg versions the modesetting driver has improved a lot, just use the driver that gives you the best experience.

Gusar · 2015-09-26 12:27:04

Lone_Wolf wrote:

It uses a generic method to drive the card

That's not quite correct. xf86-video-modesetting works by hooking into other frameworks which are very much card-specific, most notably KMS and mesa (via glamor). Without a card-specific KMS driver and a card-specific mesa driver, xf86-video-modesetting can't do anything. Well, mesa isn't strictly necessary, you'll just get software acceleration (shadowfb) instead of glamor in this case, but KMS is a strict requirement.

Last edited by Gusar (2015-09-26 12:28:59)

Maruko · 2015-09-26 12:45:26

Thank you for the quick reply! Then I guess everything is fine. I just wanted to make sure that I am not misconfiguring something here and that the card could perform better than it was in my setup.

Also thanks for the note about glxgears. I guess it has to be said again as long as it is listed first on every page when looking for a simple benchmark. Guess I'll just grab a real game for the next tests Sauerbraten has about an 8 fps difference between the two with the Intel driver working better. But as I don't play on this device I'll stick with the modesetting driver.

Arch Linux

#1 2015-09-26 11:52:13

[SOLVED]Intel GMA4500M performing worse with Intel driver than default

#2 2015-09-26 12:12:57

Re: [SOLVED]Intel GMA4500M performing worse with Intel driver than default

#3 2015-09-26 12:15:08

Re: [SOLVED]Intel GMA4500M performing worse with Intel driver than default

#4 2015-09-26 12:27:04

Re: [SOLVED]Intel GMA4500M performing worse with Intel driver than default

#5 2015-09-26 12:45:26

Re: [SOLVED]Intel GMA4500M performing worse with Intel driver than default

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