Hi, can you post the output of the top command, or gnome-system-monitor, showing the most CPU hog process? What were you doing with your computer, which apps were running? The fact that only 1 core is used is common, it depends on the application that is running. Kernel scheduler cannot turn a sequential application into a parallel one! This is in fact the reason why multicore CPUs are best suited for servers and not for dekstop usage. Let me know! <div class="gmail_quote">2008/11/25 Fred . <<a href="mailto:eldmannen@gmail.com">eldmannen@gmail.com</a>> <blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"> I am running Ubuntu 8.10 with kernel 2.6.27, Xorg 7.4, Firefox <a href="http://3.0.4." target="_blank">3.0.4.</a> I have a Intel Core 2 Duo 2.13 GHz system (dual-core, 4gb ram) I clicked on a SVG image, and Firefox froze for several minutes. ( <a href="http://en.wikipedia.org/wiki/Image:Unix_history-simple.svg" target="_blank">http://en.wikipedia.org/wiki/Image:Unix_history-simple.svg</a> ) GNOME System Monitor said that core #1 used 100% CPU, and that core #2 used 0-5%. But my whole desktop was slow and sluggish and a pain, it was crawling, it was very slow. Something is wrong here. Why was my desktop was so slow and unresponsive, when I had a whole core free under no load? Either the scheduler in the Linux kernel must be doing something wrong, or the Xorg must be doing something wrong. Which is the culprit? Where do we put the blame? Either way, this needs to get fixed. Desktop Linux cant be this way. -- ubuntu-users mailing list <a href="mailto:ubuntu-users@lists.ubuntu.com">ubuntu-users@lists.ubuntu.com</a> Modify settings or unsubscribe at: <a href="https://lists.ubuntu.com/mailman/listinfo/ubuntu-users" target="_blank">https://lists.ubuntu.com/mailman/listinfo/ubuntu-users</a> </blockquote></div>