Sluggish Output to VGA - Mini DP to DP doesnt work

[lautamas]

Hi,
I have a T430S with Nvidia Optimus graphic card.
When I put an external monitor from a VGA output, the display feels slugish compared to the original thinkpad screen (the built-in one).
I tried also on my T420 and get the same sluggishness.

Question:
1. Anything I can do to avoid this? The drivers are all updated and the resolution has been set correctly.
2. I see a mini display port on it. I have bough a MINI DISPLAY PORT to DISPLAY PORT cable (http://www.newegg.com/Product/Product.a ... 6812270261). However, when I plug in the cable, it will shows up nothing and monitor will get into power saving mode. Any idea why this can happen?

Thank You