Performance Summary and SuperAA Performance
While we only show the gains to be had from four of our sample games, there's scaling to be had on the order of 65% in Far Cry, 90% in Splinter Cell: Chaos Theory and 75% or so in F.E.A.R., all at 1920x1200 with IQ options on. In general, Crossfire does best with X1800 boards when you really push it hard. Nearly 60fps average in F.E.A.R. at 1600x1200 with 4xAA and 16xAF, and not much less at 1920x1200, is testament to its power.You simply have a massive array of 3D rendering horsepower at your disposal, if that wasn't obvious enough already. It generally scales like SLI does, mostly operating in the same modes too (from what we can tell). While ATI don't offer up any way of controlling modes, or readily seeing what's going on in general, their mantra of "it should just work" rings mostly true.
We found that in some games titles, adaptive antialiasing didn't seem to do anything when in Crossfire mode, whereas with Crossfire off it did as expected. Turning off CATALYST A.I. is something we're examining for a future piece. Crossfire still needs driver help, which is where ATI's monthly release programme and posting of BETA drivers pays off. A fix for a game is hopefully not far around the corner, if needed.
In general, plug in a 2nd board and it all goes that bit quicker or can look better at the same speed. Who'd have thought it?
SuperAA Performance
With the Xilinx doing SuperAA sample resolve now, it should be possible to get the same 12xAA performance with two boards, as you get with 6xAA on one board. Same with 4xAA and 8xAA. Double your effective multisample EER on both axes for free, basically. While that's almost always the case, as you'll see with the following Day of Defeat tests at 4x and 8x, some games will trip it up a bit. It's almost as if you could overclock the FPGA, it'd sort itself out, if that makes sense. So generally if you love your AA, X1K-series Crossfire has the SuperAA goodness you crave.
