Having a mixed up CrossFire configuration performed better than expected and was able to near the performance level of other high end ATI CrossFire setups. This goes to show that ATI has made great improvements to their CATALYST drivers, as taking an ATI Radeon HD 3870 and running it in CrossFire mode with an ATI Radeon HD 3850 was found to be stable and offered great improvements over a single card of either model. How many people will actually try this has yet to be seen, but this is an easy way to cut costs and improve performance. The lowest priced Radeon HD 3850 runs $169.99 plus shipping and the Radeon HD 3870 comes in at $209.99 plus shipping, so doing a mixed configuration will save you $40. For an extra $40 it makes sense just to do two Radeon HD 3870’s in CrossFire and be done with it. A pair of Radeon HD 3870’s in CrossFire mode out performed the mixed pair in every test, so when it comes to performance, mixing them up isn’t going to win any speed titles.
If you already own a Radeon HD 3870 or Radeon HD 3850 and find a deal that you can’t refuse on a new or used Radeon 3800 series card then it might be worth it to try something like this out. It works and performs very well considering what is being done. ATI has done a great job with the CATALYST drivers to be able to support mixing cards and brands of cards and running CrossFire. Now, if we could just get ATI to release the CrossFireX drivers, so we can do 3-way and 4-way CrossFireX with the Radeon 3800 series!
Legit Bottom Line: Mixing Radeon HD 3800 series cards can be done without losing stability and the performance gains are very nice.