I currently have a HD4890 that just isn't cutting it anymore, and am looking at upgrading to a GTX570. Now, I'm going to be buying one in a few weeks, but I also would possibly like to buy a second one sometime near December. I would like to buy a non-reference card that can clock a little higher than the EVGA's, but my main concern is that same card being available to me a few months down the road. So, if I am planning to SLI, would I be better off just going with reference cards?