slow command output scrolling in xterm + screen

Expected behaviour: ------------------- Output of ls /* whizzes by very quick. Actual Behaviour: -----------------

$ time ls /*
...
real    0m21.003s
user    0m0.082s
sys     0m0.095s

It takes 21 seconds for this command to complete. The lines scroll slowly. Something isn't right. I'm running this in screen which is running in xterm. I tried troubleshooting it but haven't figured out what's going on yet. Did find something strange though... Workaround: ------------------ For whatever reason executing this script I wrote makes it work as expected: http://sprunge.us/zdvZEO

$ fastout
...
$ time ls /*
...
real    0m1.375s
user    0m0.116s
sys     0m0.116s

Found this by chance by messing with some TERMCAP files (don't remember which ones) and noticing that the problem goes away when I cat (a portion of) the file to the terminal. What do you think could be going on and how could I properly fix this without relying on workarounds? ### Edit1: Tested this in urxvt with default settings, with the same screen session attached:

$ time ls /*
...
real    0m0.281s
user    0m0.051s
sys     0m0.080s

From this it looks like the problem has something to do with xterm or its settings. ### Edit2: To make sure it isn't any of my custom xterm settings that are doing this I've tried:

$ xrdb -remove
$ /bin/xterm

Same result. Perhaps xterm isn't at fault and it's just how gnu screen responds to being ran from xterm? Not sure yet but despite being so used to xterm for years I might just switch to urxvt which aside from not having this problem on my setup - also lets me block-select. ### Edit3: Found out that if I change hardstatus alwaysfirstline to hardstatus alwayslastline in .screenrc the problem goes away in xterm when running screen (the output whizzes by as expected). In urxvt both settings work OK. I could just change that setting and stick to xterm but I kind of want the bar at the top.