Arnold hair renders grainy/pixelated

Hey guys, I just started trying to learn XGen and how to make real time hair for hair cards and am following Adam Skutts Hair tutorial.  I'm making grey hair for an old woman, but I'm getting this noisy/grainy/pixelated look when I render out my hair clumps in Arnold.  I'm rendering at 1k with aiSkyDome light set at 0.1 and a directional light at 1.0 intensity and using the aiStandardHair shader, dropping the melanin to around .02.  Even if I crank the camera AA up to 10 it still looks grainy.  I've adjusted the levels on this image in Photoshop because it is a bit hard to see otherwise.  Does any one have any insight on this?  Any help would be super appreciated!!