Edit: I apologize, it seems that the issue was that VGA arbiter was somehow configured in the kernel, and caused a reversion to software rendering according to Xorg logs. Weird that glxinfo would report direct rendering: yes... I'll leave this instead of deleting in case someone has the same mistake =/. I don't believe VGA arbitration is required right, it is safe to disable?
Are there any currently known issues with Intel integrated graphics and linux? I am currently experiencing noticeably bad lag in general use, and am not sure if it is due to an error on my part or some incompatibility or other issue.
I am currently using gentoo-sources 3.19.0 on ~amd64 with an Intel Core-i7 4790K processor, GNOME desktop env, and just switched over from an Nvidia GTX 650 to try to use the integrated graphics instead. I was using nouveau drivers compiled into the kernel as well as VIDEO_CARDS="nouveau". I reconfigured the kernel as specified by http://wiki.gentoo.org/wiki/Intel#Kernel, as well as changed VIDEO_CARDS="intel i965" and did an update with newuse etc. After rebooting the machine, I already noticed a significant slowdown, where I previously did not usually even see any bootup messages at all. With the discrete Nvidia card and nouveau, the computer would basically boot straight into GDM login screen (occasionally I'd catch a glimpse of usual bootup messages, most often not), whereas now it scrolls through the messages relatively slowly and takes some time to get into desktop. Once in desktop, there is some screen tearing and the framerate when moving the mouse or windows is noticeably lower. lspci -k indicates at least the kernel driver is loaded, and glxinfo indicates that direct rendering is enabled. I can't imagine that the actual performance would be this poor, so there must be a problem.
Any help in troubleshooting this is greatly appreciated, thanks!
