bringing up *any* browser cripples system performance

[Robert P. J. Day]

  (note: i'm starting a new thread for this since my original post
blaming firefox for system slowdown now seems inaccurate. the problem
appears to be more widespread.)

  the system: an asus g74s, quad-core i7 with 16G of RAM, so i'm
fairly confident that physical limitations aren't the problem. to
establish a baseline, i'm in gnome 3 with only a couple terminal
windows open, no browser. performance is snappy -- when i move the USB
mouse, the cursor moves appropriately, nice and crisp. and "top" shows
Xorg puttering along, using in the neighbourhood of 5-10%. all in all,
everything working just fine. oh, using the
3.15.0-0.rc0.git9.1.fc21.x86_64 kernel as well.

  now i start a single instance of epiphany, and i have a single tab
open on a page of my web site wiki which contains nothing but text --
that is, no gifs, no video, nothing like that. performance still seems
fine, but now i go to simply move the epiphany browser window and
response just plummets. simply dragging the browser window to a
slightly different location is painfully slow and jerky, and Xorg CPU
usage jumps to 50%. as soon as the move is over, Xorg CPU usage drops
back to normal.

  slightly different experiment -- just try to resize the browser
window by dragging a corner, again horribly slow and Xorg usage
briefly jumps to 88%. in fact, just moving the cursor *across* the
browser window causes it to slow horribly. and i tried this from a
throwaway guest account, same symptoms. (all of this matches what i
saw with firefox, which is why i switched browsers, but i see exactly
the same problems.)

  and trying to watch a youtube video is practically futile. i opened
up a second epiphany tab and popped over to
http://www.youtube.com/watch?v=0bXSeheZLq8. interestingly, while audio
seems fine, i'm lucky to get one or two frames per second, the video
is that erratic. and while the video is playing, Xorg is up around 90%
CPU usage and keyboard response while typing this has a massive time
lag.

  this system has an nvidia chipset, and here's the relevant
nouveau-related "lsmod" output:

$ lsmod | grep nouveau
nouveau              1178761  3
mxm_wmi                12865  1 nouveau
i2c_algo_bit           13257  1 nouveau
drm_kms_helper         50413  1 nouveau
ttm                    85373  1 nouveau
drm                   288814  5 ttm,drm_kms_helper,nouveau
i2c_core               38734  6
drm,i2c_i801,drm_kms_helper,i2c_algo_bit,nouveau,videodev
wmi                    18804  3 mxm_wmi,nouveau,asus_wmi
video                  19456  2 nouveau,asus_wmi
$

  i have to think this is something related to nouveau since nothing
else seems to explain it. is there some kind of gnome setting i can
play with to see if that helps? i'm open to suggestions.

rday

-- 

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Robert P. J. Day                                 Ottawa, Ontario, CANADA
                        http://crashcourse.ca

Twitter:                                       http://twitter.com/rpjday
LinkedIn:                               http://ca.linkedin.com/in/rpjday
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