Star Brood wrote:
The StarTech one goes for $30 already, MORE is not what I am looking for, lol. And that is a Mini DisplayPort variant. I guess I am just too spoiled by seeing HDMI and DVI cables going for <$5 that this DisplayPort adapter goes for so much more.
The difference is that there is dedicated video processing (and pretty high speed electronics) in an active adapter. The active adapter converts the true DP signal, which is a packet based signal along the lines of Ethernet, USB, and PCI, to a DVI signal which is a high speed synchronous (has a separate clock signal) serial bus. The converter has to buffer the incoming DP data packets, serialize them, generate the DVI display clock, then send the data out over the DVI connection. This is different from the passive DP->DVI adapter which will only work on a Dual-mode compatible ports. The "passive" adapter simply does signal voltage level translations. The dual-mode DP port actually generates the DVI format compatible signals.
The reason you have to have an active adapter is that the 7850 can only generate two DVI clock signals on the card. This means it can only directly drive two DVI based displays, regardless on which connector you use. The active DP->DVI adapter takes care of generating the third DVI clock that the card cannot.