Although the CrossFireX configuration built out of two Radeon HD 5750 was overall superior to the single Radeon HD 5850 and the two Radeon HD 5770 were faster than the single Radeon HD 5870, I wouldn’t say that they are preferable. The problem is that the CrossFireX tandems are often inferior in terms of bottom speed due to the AFR rendering mode and 128-bit memory bus. The latter shows up in high-quality modes and at high resolutions. So, while CrossFireX boosts the average frame rate to the level of top-end graphics cards, the bottom frame rate remains rather low. And it is the bottom speed that determines the level of playing comfort.
Considering the results of this and earlier test sessions with Radeon HD 5770 and HD 5750, including those at overclocked frequencies, purchasing two inexpensive Radeon HD 5750 cards and overclocking them to 850/5000MHz seems to be the most profitable option. At such frequencies, the cards totaling $250-260 will be faster than a single Radeon HD 5870 which currently costs $400 or more. The difference can be spent for a good mainboard and a couple of CrossFire bridges (the XFX Radeon HD 5750 comes without them, for example). So, this configuration seems appealing indeed.
The XFX Radeon HD 5770 and XFX Radeon HD 5750 cards discussed and tested in this review are good products following the reference design. The only thing I can complain about is that there is no CrossFireX bridge in the XFX Radeon HD 5750 kit, but the rest of the accessories are up to the product class. As these are one of the early Juniper-based cards available on the market, they do not have pre-overclocked frequencies. But XFX is known for its pre-overclocked products and I have no doubt the company will release such versions soon.