Abra um terminal, digite:
glxgears
Espere um pouco feche e cole a saída aqui.
Você deve ver uma saída mais ou menos assim:
[lsbrum@ubuntu:~] glxgears
Running synchronized to the vertical refresh. The framerate should be
approximately the same as the monitor refresh rate.
22778 frames in 5.0 seconds
22225 frames in 5.0 seconds
XIO: fatal IO error 11 (Resource temporarily unavailable) on X server ":0.0"
after 44 requests (44 known processed) with 0 events remaining.
[lsbrum@ubuntu:~]