t420 nk6 独显外接显示器，屏不定时出现条纹

hardaway789

简单说一下，BIOS 启用独显，外接显示器，笔记本屏不定时会闪条纹，有时隔几十秒，有时隔几分钟。
不外接或外接显示器用集成显卡，或是设置自动选择，则没上面的问题
试各个版本显卡驱动，没用。试过别的显示器，连接线也没用。
下面是我上网找的，有一位跟我一样的问题

Hey everyone,

I'm having a weird issue here with my T420 - I'm running it in discrete graphics only mode (Optimus disabled - just the NVS 4200m alone).

Whenever I have an external monitor connected via the DisplayPort connection, the laptop's onboard LCD briefly flickers from time to time (especially when something changes the state of the graphics card, such as opening up the NVIDIA control panel and selecting the 3D graphics settings preview tab). It's actually not just a flicker - I see a set of vertical lines appear on the left half of the screen for a split-second.

This only occurs on the onboard LCD - the external monitor looks just fine.

Anyone else experiencing this? I've been trying all sorts of things - different external monitors, different DisplayPort-DVI adapters, different versions of the NVIDIA drivers, with no luck.

My specs are:
Windows 7 Professional x64
Core i7-2620M
NVIDIA Quadro NVS4200M
8 GB RAM
Intel 510 120GB SSD
14.0" HD+ LED backlight Anti-Glare (1600 x 900)

我的配置跟他差不多，是I5-2430的CPU，显示屏也是高分屏


请教一下，怎么解决问题？

yaole2

或是设置自动选择，则没上面的问题