ATI Radeon CrossFireX Review - Scaling in Eyefinity

Like the widescreen performance, CFX scales will in Eyefinity as well. Though the scaling is slightly lower, 50% - 70% improvement isn't bad considering you're pushing between 5.3M and 6.9M pixels. While CFX is overkill for widescreen, it can provide a significant performance boost for Eyefinity. Putting a 5870 or 5850 in CFX often means the difference of moving above 60fps in Eyefinity (at max settings).

While there is little to no difference between the 1GB 5870 and the 2GB 5870 E6 in widescreen. However, there is a measurable difference in CFX performance for the 2GB card. And, this observation goes beyond the issues with Batman, Heaven and STALKER - where the 2GB card is needed to simply launch the game at 5760x1200. The 2GB card offers smoother play (i.e., fewer stutters), as we saw in Far Cry 2. It also appears to loosen an Eyefinity bottleneck with 1GB cards in CFX.

The 5850 often performs close to the 5870 - except STALKER and the Heaven demo. I would love to see two of the custom HD 5850 2GB cards in CFX. Those run close to the 5870 1GB card in price, but the two I found were overclocked in addition to sporting the 2GB of VRAM. The 5850 2GB runs about $100 less than the 5870 E6, and would pull lower power and heat.