R700: First previews of the HD 4870 X2
Before all else: You have to keep in mind, that the Catalyst drivers used for the tests are not final, yet. Furthermore both sites were not allowed to present more than four game benchmarks. Additionally the idle power consumption had to be kept secret, because Powerplay has not yet been integrated correctly.
While Anandtech used a Intel QX9770 on a 790i SLI board, Hexus took a QX6850 on a 680i SLI respectively and Intel X48 board. The drivers were the Catalyst 8.6 Press Release 5 (Hexus) or the 8.7 Beta (Anandtech). The cards themselves didn't differ much, besides the black PCB, from the HD 3870 X2, even the rumored 2,048 MiByte video memory are missing.
In every benchmark the Radeon HD 4870 X2 behaves like a Crossfire team of two HD 4870s. In Age of Conan for example the card is way ahead of two (!) GTX 280, in the Hexus Crysis benchmark on the other hand it loses against the Geforce card. It seems like Crossfire is not working properly in Crytek's shooter - a single HD 4870 receives equal results. In situations where crossfire is working, it scales excellent with about 80 to almost 100 percent - a GTX 280 stands without a chance. Therefore the HD 4870 X2, in principle, offers a great performance, which nevertheless depends on the driver.
Under full load the dual GPU card needs in combination with the other components of the Anandtech setup 407 Watts - this is 30 percent more than the GTX 280. In the Hexus system the difference is even higher: 395 Watts equal 40 percent higher energy consumption. In opposition to AMD's restriction the idle consumption was recorded, too, which with 242 Watts is alarmingly high - the GTX 280 needs about half as much. Regarding the loudness the Radeon and the Geforce are equal noisemakers.
Please bear in mind, that performance, power consumption and loudness of the final card can differ from the results shown here.
Grafikkarten-Rangliste 2016: 32 Radeon- und Geforce-GPUs im Benchmarkvergleich [Oktober]