We take AMD's Catalyst 13.8 beta driver for a spin to see if its frame pacing feature fixes CrossFire's dropped and runt frame issues. Follow along as we compare the Radeon HD 7990 to Nvidia's GeForce GTX 690 in seven popular titles, with video to match!
Earlier this year, Nvidia introduced its Frame Capture Analysis Tool, giving us the ability to measure graphics performance in a new way. In essence, we capture the signal coming straight out of the DVI port losslessly, recording it onto an array of SSDs. The video file is sent through a series of Perl scripts that tell us how long each rendered frame is on-screen. This process incidentally also lets us know if a frame is clipped super-short (referred to as a runt frame) or if it doesn't show up at all (a dropped frame).
You can read more about the testing we've done using FCAT in Challenging FPS: Testing SLI And CrossFire Using Video Capture, and also in any number of the graphics card reviews we've published since then. To make a long story short, though, on multiple occasions, we've shown that two AMD Radeon graphics card working cooperatively in CrossFire incur a significant number of dropped and runt frames as both GPUs try to render as quickly as possible. Because those frames aren't perceived as you game, the benefit of having two GPUs decreases. Nvidia avoids this through a metering technology that deliberately displays frames in a more consistent manner.
At its best, critical journalism can be a catalyst for change (no pun intended). AMD let us know several months ago that it was working to implement a frame pacing feature in its driver that would similarly meter out frames, inserting small delays where necessary in order to display them at a consistent interval. As you no doubt already know, frame pacing made its debut late last month in the Catalyst 13.8 beta driver. The feature is turned on by default, and company representatives say that observed frame rates shouldn't be negatively affected in most games.
AMD's work is far from over, though. Its 13.8 driver is the first step in this new direction. But support for frame pacing is limited to DirectX 10- and 11-based games on one monitor at resolutions up to 2560x1600. That means it doesn't work in DirectX 9 games, OpenGL-based games, or in multi-monitor arrays. Compatibility with those APIs and technologies will follow in a phase-two driver, though there's no estimate for its arrival. Eyefinity is probably the biggest loss, since the scaling of CrossFire practically begs for a three-screen setup. We'll take what we can get though, and we're eager to put AMD's implementation of frame pacing through our suite of tests using one display at 2560x1440.
The Catalyst 13.8 beta driver also offers OpenGL 4.3 support, though of course it doesn't work in conjunction with frame pacing. The beta driver accommodates saving custom OpenGL settings on a per-application basis, and Catalyst Application Profiles (CAP) updates also add OpenGL-based titles. In addition, AMD claims a performance speed-up of up to 7% in Metro: Last Light.
You probably noticed that the Radeon HD 7990 is down $300, from $1000 to $700. Although AMD's flagship is more power-hungry than Nvidia's GeForce GTX 690, and not suited, we determined, in quad-CrossFire configurations, there's no way to simply shrug off such a huge price cut. With that in mind, this is a great opportunity to reconsider the 7990 with an update purported to fix the issues we discovered back in April.