Before we dive into the questions above, there is one topic that has been burning on our minds to talk about since we've been testing a lot of SLI and CrossFire lately. We need to discuss where we are in terms of SLI and CrossFire smoothness and frametimes. That old issue about choppy or stuttering gameplay under SLI and CrossFire which we have been addressing subjectively for many years now.
In the past it was commonplace to complain about stuttering or choppiness with any AMD CrossFire solution. Times have changed, and we actually find that the roles have now reversed, at least at 4K. AMD has introduced its frametime averaging technology and is fully implemented on AMD R9 290X. AMD R9 290X also introduced new CrossFire technology that does not require a bridge atop the video card and improves communication through the PCI-Express bus. These improvements have proven to be successful in reducing the awful stuttering AMD used to be known for with CrossFire.
In all of our gaming we have shown you today, in every single game AMD CrossFire feels smoother to us than NVIDIA SLI. That's right, the tables have turned on this issue. In fact we experienced many situations where there was choppiness or stuttering with the two ASUS STRIX cards in SLI. It was noticeable, and when we switched to AMD R9 290X CrossFire; CrossFire just felt smoother.
One example of this is in Crysis 3. When we ran 4X MSAA at 3840x2160 with "High" settings we had a smooth experience with ASUS R9 290X CrossFire. However, with ASUS STRIX 780 6GB SLI we had a definite stutter, non-smooth experience despite what the framerates read and despite having 6GB of VRAM. This is a case where the framerates were reading what looked to be playable, at times in the 40's of FPS yet the actual gameplay felt choppy, like it was under 30 FPS! This is exactly the type of phenomenon we used to experience with AMD CrossFire.
Another example of this also happened in Far Cry 3 even running at just 2X MSAA "Ultra" settings. Our experience was altogether smoother with AMD CrossFire. It was as if the numbers we were seeing in FRAPS wasn't matching what we actually felt in game with SLI and this is exactly the way it use to be with AMD CrossFire.
Yet another example is the actual frametime results we have from BF4. Since we are now running that game under Mantle on AMD cards we have to use its built in frame time recorder and from that derive the average framerate. This displays to us the actual frametimes of the game. We often find that the AMD CrossFire frametimes are less than (better) than the NVIDIA SLI frametimes in the game. Granted we are using Mantle on AMD cards, but we have seen that to be true.
Today we can confidently state that AMD CrossFire is going to give you the better gameplay experience than SLI at 4K.