Ramblings from another nerd on the grid
Lenovo continues to make perplexing choices with some of their machines. One such choice is the change to how Optimus operates on the ThinkPad T430s notebook computer. The T430s Optimus implementation with the Ivy Bridge chipset is very different from the implementation in the ThinkPad T420s.
Lets review some of the evolution of Optimus. Way back towards the tail end of the ThinkPad T410s sales cycle, Lenovo introduced a dual GPU implementation branded Optimus which is a NVIDIA trademark. I blogged about the T410s at http://blogs.technet.com/b/keithcombs/archive/2010/11/14/driving-four-dell-lcd-panels-with-a-single-lenovo-thinkpad-t410s-optimus-laptop-and-dock.aspx. As you can see in the picture, I am driving three external LCD panels. There is actually a fourth LCD connected sitting on the floor out of the field of view.
When the T420s came out, obviously this was tested right away and it passed with flying colors. Three of the LCD panels are connected to ports on the Series 3 docking station and the fourth is connected to a port on the notebook itself.
Last week my wife’s ThinkPad T430s arrived and like any good geek I started testing it to make sure it is a keeper. One of the first tests I did was to test multimon. I dropped the T430s into my dock and… uh oh. It would only drive two LCD panels. Now to be perfectly honest, I had already read this was an issue with the T430s but didn’t believe it. Why on earth would Lenovo cut a feature like that? I know MANY people that use more than two displays at a time. Probably everyone in Microsoft Support does.
I tested this several different ways using the connections on the 135W Series 3 dock I have. It simply wouldn’t work. I shot a message off to our internal Lenovo discussion list and Michael Jeremica looked into it. As it so happens, there is a Lenovo KB making the rounds at http://support.lenovo.com/en_US/downloads/detail.page?DocID=HT074304. There is a key hint in the Solutons section of that document. In order to get a third LCD panel to display, you much use a connection from the laptop itself. After connecting my StarTech mini DisplayPort -> VGA adapter into the mini DP port on the T430s, the LCD panel lit up.
This is not ideal, but three external panels is better than two.