carodan, I appreciate the suggestion, and was actually thinking the same thing. I KNOW the inside of my computer is incredibly dusty ... perhaps the memory DIMM contacts are affected. Cleaning it can't hurt. :-) This problem has me perplexed, as Poser never "choked" on complex renders when I was using 1/4 my current memory. Thanks for the responses regarding SR1. I didn't think it mattered but wanted to be sure prior to installation. I'm crossing my fingers. :-)