x201s/x201 external display hangs problem

I used my x201s with docked 24" external monitor for 2 days, the problem happened very often. I also found similar reports from lenovo forum:

http://forum.lenovo.com/t5/X-Series-ThinkPad-Laptops/x201s-External-display-issues/td-p/218624

http://forum.lenovo.com/t5/X-Series...1-hangs-randomly-while-logging-on/td-p/213630

For convenience I put them together, hoping to get an answer.



My symptom:

x201s with 24" external monitor@1920*1080 docked power-on(ultrabase docked, displayport to HDMI converter) starts very slowly, often stuck at the windows 7 welcome screen, it hangs randomly while logging on windows 7.(After enter the password / fingerprinter) The circle next to "welcome" went slow, sometimes the screen went totally black.

usually when the X201S feels 'happy', I get the power-on POST screen on my external display, and everything works-fine from there. When I don't see the POST screen, I know I'm going to hit some trouble.

the display driver crashed/recovered several times. "Display driver igfx stopped responding and has successfully recovered."

I believe this problem is caused by the display driver. The driver from Lenovo website is not the latest (Version: 8.15.10.2025 Release Date: 2010/01/29). I downloaded the latest one from Intel(Version: 8.15.10.2086 Release Date: 2010/03/04) but I couldn't install it properly.

I tried many other ways, even re-installed the whole system. At last I found a setting in the BIOS "Config---Display---Boot display device", the default setting is "thinkpad lcd", i changed it to "Digital on Thinkpad (displayport)". The problem happened less frequently, but still happened occasionally.