I have an old ati radon ha 5870 from a former gaming rig, but lost all the adapters. My wife's current computer has a gt710 that bare gets bye on games like skyrim. Can I put the stronger ati in her machine and have it do the hard work while the gt710 handles the connections?
Are you talking about power adapters? If the PC doesn't have the correct ones then it is likely not strong enough to run the card to begin with. Which PSU is it?
I have the power connectors for it. That's not the issue. The video card currently in her comp is very weak, but has hdmi ports. My old gaming card I want to put in there has plenty of power, but proprietary ports and short cords to convert to whatever connection you need. I'm missing all of my cords as I got that card over 5 years ago. I'm wanting to use the low end card as basically the hdmi port for the bigger card.
That's generic. Ati is the maker of the GPU chip: the HD 5870. Other manufacturers actually sell the final product. There usually isn't anything proprietary but they often include adapters to convert the mini-ports to the full sized ones. I think this is what you are looking to get.
If you can't identify which one it is, please take some pictures of it, especially the proprietary socket and any writing or stickers, and put them on an image hosting site and then put the links to the picture in this thread. We will help to find what you need.