I have identical symptoms after my recent upgrade, so I thought that I add my observations. I bought Lenovo T520 (90% intel based devices) and was migrating everything from old R61. I installed core version of newest Arch, setup ssh session between two notebooks and wanted to copy HDD contents, as I always did when I switched notebooks. But I couldn't due to constant ssh connection problems. I tried turning off various TCP offloads with ethtool, but it didn't help. I ended up copying the data via the external HDD. As there was no X running on those computers, I don't thing that the network problems are X server related. But there are also those: * Firefox random crashes. After a reboot it runs for 10…15 minutes and then starts crashing like hell. HW acceleration disabled, no Flash plugin, but still crashing. GDB stacktrace shows segfaults in /usr/lib/firefox/libxul.so preceeded by a couple of calls in libpng. * There were problems with Flash alone, too, but I worked around them by: 1. disabling "Hardware acceleration" in right-click Flash config, 2. exporting VDPAU_NVIDIA_NO_OVERLAY=1 in /etc/profile, so the whole X sees it). When Fx is not crashing, Flash works well. * Mouse cursor jumping to the top, left or top-left corner. Clicking on any button fixes the problem, but it keeps recurring very quickly. * X crashes. Usually when Firefox starts crashing, the problem with mouse occures and X crashes, leaving me with KDM. Fx and mouse problems return quickly even if I restart X (the kdm daemon), so it might be a problem with kernel rather than X. My desktop environment is KDE 4.7.3. What I tried until now: * Two graphics cards: integrated Intel and Nvidia NVM 4200M, with and without acceleration, with and without compositing). Couldn't test Nouveau, as it says that my chipset is not supported. * Disabling touchpad in BIOS. * Updating to 3.1.2 kernel yesterday. * Slowing down all cores to 800Mhz (like it was thermal problem). Neither of the above helped for any of the problems. Since Ciprian was using i3wm, which is very different from KDE, I wouldn't blame DE for these problems. I have Windows 7 on this notebook, too, and everything works fine there. I didn't test custom built kernel, but I'm going to do this now. std::best_regards(); -- Michał Gawron