Conclusion

The two Radeon R9 390X 8GB do scale really well, when driven CrossFire. Apart from that it is interesting to see that the scaling gets better, the higher the resolution is set. In other words, the higher the graphics load, the more the system benefits from the second graphics card.

1080p

A closer look at the results gathered, when testing the game at FullHD, we see that on average the frame rates go up by 53%. Games like Tomb Raider, Crysis and GTA 5 scale exceptionally well, which means, there is a 90% performance benefit. On the other hand there are Thief and Grid, which don't scale with the second card at all.

1440p

With the resolution set to 1440p the overall picture already looks a bit different. On average the performance goes up by 68% and the games do benefit more from the second card. We find very good scaling (>90% higher FPS) with Tomb, Raider, Sleeping Dogs, Far Cry 4 and GTA V. There are also quite a few games which perform 70% to 90% better: BattleField 4, Crysis 3 and Metro Last Light. Overall scaling is very good at this resolution.

2160p

As we already mentioned, with UHD (2160p) we find the largest performance improvements. On average a second card helps boosting frames per second by 76%. BattleField 4, Tomb Raider, Crysis 3, Sleeping Dogs and GTA V show more than 90% higher frame rates, whereas in Metro Last Light and Far Cry 4 fps go up by more than 80%.

Power Consumption

The AMD Radeon R9 390X is not known for being the most power efficient card, which becomes even clearer, when checking out the consumption values. In idle our test setup, equipped with one card pulled 64 Watt and with the second card added power consumption went up to 77 Watt, which is a 20 percent increase. Under load, the single card setup needs 344 Watt and the 2-way CF system pulls 635 Watt. This equals to 84% higher power consumption.

Recommendation

Should you be thinking about buying a system with two Radeon R9 390X graphics cards, then you should check which games you're actually playing. There are some games, which do not scale at all with CrossFire setups. Those games, which actually benefit from a second card, the receive a great boost. Most games show 70% to 90% higher frame rates. Nevertheless there are also some games which only run about 30% faster. You should also keep in mind that two Radeon R9 390X consume a lot of power and therefore we recommend a power supply with at least 750 Watt output power to be on the safe side. In our opinion a system with two Radeon R9 390X 8GB cards makes a lot of sense if you want to play games at UHD (2160p) resolution.

Page 1 - Test Setup

Page 2 - Synthetic Benchmarks

Page 3 - Games

Page 4 - Power Consumption

Page 5 - Performance Index

Page 6 - Conclusion