AnandTech has taken a look at the competitiveness of the AMD Phenom II X4 940 platform with CrossFireX, you can check it out over here. In this article the site compares the Phenom II X4 against a similar Core 2 Quad system.
One such question arrived in droves after our Phenom II X4 launch articles a couple of weeks ago. We had to dig through many of the “You guys always favor Intel and NVIDIA...” comments (for the record we favor performance, quality, and value regardless of supplier) but after some sifting, we found a pattern in the messages. Many people wanted more information concerning gaming performance between a Phenom II X4 and similar Core 2 Quad system with specific setups. We covered these two platforms and more in our Phenom II launch article. A treasure cove of further information is available in our new Bench database, especially for those who do more than gaming on a computer.
The site concludes a Phenom II is competitive with a similar Intel platform in CrossFireX, but notes that if the Core i7 platform was a bit cheaper it would have a clear recommendation for an upgrade if you were considering a multi-GPU setup.