Overclocking And Eyefinity
Let's start with overclocking. We used only the most basic overclocking method for this review: the Overdrive settings within the Catalyst Control Center.
Our reference model didn't complain in the slightest when pushed to the highest allowable settings: 850 MHz core and 1050 MHz memory. This resulted in a respectable 75 and 50 MHz overclock, respectively:
To test the effectiveness of this overclock we benchmarked the card at 1920x1200 in two of our staple titles, Far Cry 2 and Crysis:
As you can see, the overclock resulted in an impressive performance increase in Crysis at the 1920x1200 resolution, and a small (but recordable) increase in Far Cry 2. This plus the fact that the Radeon HD 5670 reached its maximum allowable overclock so easily gives us good reason to wonder what the card could accomplish with some serious overclocking tools and voltage tweaks.
As for Eyefinity, we wanted to see how well the Radeon HD 5670 would work at AMD's suggested 4800x900 (three monitors running 1600x900) resolution. Unfortunately, without a DisplayPort monitor or adapter for the card's third output, we had to try something a little different. Since 4800x900 is about a 4.3 million pixel workload, we created a similar 4.6 million pixel workload using two monitors and a 3840x1200 resolution.
While Crysis didn't offer us a 3840x1200 resolution option (we could have forced it through some trickery, but we were pressed for time) Far Cry 2 did. Here are the results of running Far Cry 2 at this setting compared to 1920x1200:
As you can see, pushing pixels at this unholy resolution is not something that the Radeon HD 5670 is well suited for, but it did yield a 30 fps average. It's possible that lowering details or playing a less demanding game would provide better results, but if triple-monitor gaming is your desire, we heartily recommend moving up to a more powerful Radeon HD 5700- or 5800-series model, at the very least.