Who's the Stutterer?
Quite simply, AMD CrossFire is the stutterer in the room. We have talked about this issue in every CrossFire versus SLI evaluation we have published for years now. We are pleased to say it felt like stuttering has been lessened a bit with AMD CrossFire. However, it is still very much a reality with Catalyst 13.5 Beta2 on Radeon HD 7990 and 7970 GHz Edition CrossFire. First of all, we experienced no difference in stuttering between the single-card Radeon HD 7990 and two-card Radeon HD 7970 GHz Edition CrossFire. The amount of stutter or inconsistency felt the same between both configurations while gaming. The fact that two-GPUs are hardwired on a single PCB didn't reduce the stuttering as some might have thought. We feel that driver improvements are slowly getting there. This new driver so far as the "best" experience we've had yet in regards to stuttering.
We did feel a smoothness difference between AMD CrossFire versus NVIDIA SLI. Let me describe a moment I had while gaming on GeForce GTX 680 SLI in Crysis 3 during this evaluation. I had begun my apples-to-apples testing first with the GeForce GTX 680 SLI in Crysis 3 and was running at 5760x1200 with very high settings and SMAA 1X in the game. I started the run-through, and as I was playing through the entire level of "Safeties Off" I was borderline calling it playable at that setting. I didn't know the FPS, as when I'm recording with FRAPS the FPS is not displayed. (We do this purposefully.) Therefore, all I could feel was the game itself and I wasn't burdened with thinking in FPS at all. It was a fluid and immersive gaming experience. The game to me felt like it was playing at 40-50 FPS. Finishing up the run-through I stopped FRAPS and it read an average of 33 FPS.
I was in awe. It felt smooth, really smooth, it felt like it was running at a faster framerate than it really was. If not for some minor lag throughout the run-through, I would have called that very high setting playable based on the experience alone, without looking at the framerate. It was a shock to see the framerate so low, I really thought it was higher as I was playing. This kind of smoothness we often experience with NVIDIA SLI. This cannot be said for AMD CrossFire. It stuttered badly at very high settings and you knew, you could feel it that it wasn't playable as it negatively affected the overall gameplay and immersion. While this is a broad statement, it stands up fairly well even though there are differences using different game engines: It takes higher framerates to get a smoother experience with CrossFire than with SLI.