I see this kind of behaviour too, but then specifically with very long lines (a sipXproxy.log). The lines span about 5-6 rows of my very wide konsole window. The same file scrolls very quickly in xterm.
It seems that konsole is taking up the entiry CPU and given the modern cgroup configuration in ubuntu 12.04, the remaining cpu doesn't get used for other windows... :-(
I see this kind of behaviour too, but then specifically with very long lines (a sipXproxy.log). The lines span about 5-6 rows of my very wide konsole window. The same file scrolls very quickly in xterm.
It seems that konsole is taking up the entiry CPU and given the modern cgroup configuration in ubuntu 12.04, the remaining cpu doesn't get used for other windows... :-(
/Simon