EDIT, 3/22/14: I just noticed that the instructions say the signal is only passed through passively, and only on DP++ ports. Well, my Dell Optiplex is only DP, and passes the video just fine. I frequently watch videos in Prime online here at Amazon, and have no problems, using the same Optiplex 780, as in the original review, following below. ======================= I am the happy owner of a Toshiba 19L4200U LCD TV which I got here at Amazon a few months back (see my review). I wanted to use it as a second monitor for my new Win7 Pro (well, used, from dellauction) Optiplex 780. Mistakenly, I thought the latter had an HDMI port, but it's a Display Port, and it won't transmit sound. Not to worry: I bought this here, plugged it in last Sunday, and bang! Works just fine. That matters, for the max resolution advertised, is as far as the Toshiba can go. But here's the important trick: you won't GET that resolution unless you configure your dual monitors to spec the TV, first. Always pick the monitor/TV with the HIGHER resolution as the first in the pair. The second, being lower, will default to the lower resolution. IF you don't do this, you 'cage' your higher-resolution monitor/TV to the lower resolution of the other one. Extended Monitor versus Dual: the latter duplicates what you see on screen. The former, effectively INCREASES the screen width. So you could make a really big window on the 'primary' screen, with its overflow on the other screen. The only time to do that, is when you have to view two things side by side in a size too large to fit on one screen: or, if your application lets you specify one monitor, versus another. There are other instances also, where dual screens are of value, but I can't think of them right now. PS: if you have problems with installation, it means your monitor settings or the Display Port settings need to be changed. For example, my TV requires me to set its 'input' mode to 'HDMI2', as that's the port into which the HDMI cable goes. So if I'm using the wrong 'input' mode for my TV, I can't see anything on screen. That's not the fault of the adaptor. That's a setting problem on the machine.
