However, SLI AA has its limitations, including what I would consider unexpectedly poor performance in many cases and an apparent incompatibility with Half-Life 2. I haven't had time to test SLI AA yet as extensively as I'd like, but my brief experience with it over the past couple of days has been rather shaky. I wouldn't call SLI AA a sensible tradeoff of performance for image quality in most situations. SLI 8X mode is too often slower than NVIDIA's regular 8xS mode and offers a near-imperceptible improvement in AA quality. SLI 16X mode only makes sense in heavily CPU-constrained games that offer acceptable performance almost no matter what the graphics subsystem is doing. Perhaps the picture will look different given more time.