A advantage that AMD gives us over nVidia is the ability to crossfire different AMD GPUs (being that both either need or don't need a physical bridge). So lets say you had a R9-290 and then you got your hands on a new R9-390. Sure the R9-390 is going to have many perks over the last gen, but what if you offloaded some of the number crunching onto the the R9-290? Well the results may surprise you, I was able to get some impressive results when comparing a Solo R9-390 to a R9-390 & R9-290 Crossfire. Check this out.