I'm running a pretty modest machine with Win7 64-bit, and I've had no trouble at all out of DAZ Studio 4 so far. I think the new UI really cleaned things up. I also love the new Genesis figure, and I can't wait for the morph and character packs to hit the market. I'm also anxious to see which tools are going to be updated and which are not. The only negative I can really point to is that I think DAZ rushed DS4 out the door before they were really ready: there should have been at least a few components available to flesh it out. Instead, all there is at the moment is the AutoFit Tool (which costs $50 on sale) which I STILL have not gotten a firm yes or no as to whether it will be included with DS4 Advanced or DS4 Pro.