How can I set up a second monitor using the DVI, a mini Displayport to dvi?

Question

Hey guys,
In my office I'm trying to set up a mac with two displays, Samsung screensync sa450s, using a Startech MDP2DVIW mini displayport to dvi, and the DVI port found on the ATI Radeon HD 5770.
However, whichever monitor is plugged in through the mini displayport never shows video, and instead will just flicker sometimes, no matter which monitor I use, or which of the mini displayports i use. The system profiler recognizes both monitors, and has all of the specs on both monitors, but only the monitor connected directly to the DVI displays anything, even if it is the secondary monitor.
The StarTech does still work with the macpro that used to be in this spot, and the only salient distinction I can find is that the old computer has Mountain Lion, while the new one is still running Snow Leopard. Is this a case where we should just update the OS? or is there another fix?
I've also read online that many people have been not fully plugging in these mini displayports, so I'm worried that I'm doing that, but then I'd figure it wouldn't have worked when I plugged it into the old computer unless my predecessor had made some hardware adjustments.
Let me know.

Answer 1

A frequent solution to problems like the one you describe involves pushing in the Mini DisplayPort cable-end.
It should be inserted until essentially ALL of the metal end disappears inside the jack on the 5770 board.
Is this display wider than 1920 wide?
EDIT:  The Startech MDP2DVIW adapter you cited is a passive adapter suitable for 1920 wide or less. You should be using ACTIVE adapters, about US$35. They cost a little more, but are much more trouble-free. The ACTIVE designation means they contain booster circuitry to raise the Voltage levels up to true DVI levels. The default converter produces good timing, but the signals are really low.