VTd is the 'virtualised device' acceleration within the CPU - it has been very problematic with the igfx so far, but supposedly Ivybridge works. intel_iommu=off disables support and thus allows the GPU to have direct access to memory without going through a DMA remapper.
-- You received this bug notification because you are a member of Ubuntu-X, which is subscribed to xserver-xorg-video-intel in Ubuntu. https://bugs.launchpad.net/bugs/1137817 Title: [ivb] System freeze after high memory usage To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-intel/+bug/1137817/+subscriptions _______________________________________________ Mailing list: https://launchpad.net/~ubuntu-x-swat Post to : ubuntu-x-swat@lists.launchpad.net Unsubscribe : https://launchpad.net/~ubuntu-x-swat More help : https://help.launchpad.net/ListHelp