Given this chart, you can Crossfire HD 5970s and HD 5870s. Whether or not you can do it with a three card scenario, I can only recommend trying (for curiosity's sake). Of course, your motherboard would need to support more than just two cards and the cards would need multiple Crossfire Connect ports.
-Wolf sends
P.S. Only NVidia required identical model graphic cards for SLI set ups.
No. I don't think you can crossfire those 2 different GPU models.
NEVER MIND......
Btw, there is not point in going for a multi-GPU setup like SLI or Crossfire. It's not worth the hassle these days. You would be much better off buying a SINGLE powerful GPU instead.
Given this chart, you can Crossfire HD 5970s and HD 5870s. Whether or not you can do it with a three card scenario, I can only recommend trying (for curiosity's sake). Of course, your motherboard would need to support more than just two cards and the cards would need multiple Crossfire Connect ports.
-Wolf sends
P.S. Only NVidia required identical model graphic cards for SLI set ups.