So, I'm not savvy enough to remember how to print out bug reports from match logs and all that, but Scarponi helped me check the memory levels on the match I was doing using the "stats" command - and they seemed a mite high. Over the course of my completion of the Centurion Challenge, memory levels hit as high as 270,000 or so, with big slowdowns happening every time a card was drawn, and minor slowdowns every time one was discarded. It's not a simple matter of my computer needing an update, either - I was able to preform other tasks just fine... as long as a card wasn't being drawn or discarded in the meantime. It made what should have been about 40 minutes of play take me about two and a half to almost three hours. I know just enough about memory leaks to suspect this might have been one.