Well, your machine specs look pretty good. You have twice as much RAM as I do, although I'm running a 2.8 Northwood Pentium chip. Firefly does get resource heavy while rendering, admittedly, but we may be able to find some workarounds. I have to get back to work for now (I'm taking a break to check on this thread), but please be sure to open this for discussion tomorrow. We're trying our best to make P5 as competitive within the market as possible, which has been difficult until recently because Curious Labs did a horrible job of presenting most features in the documentation (not to mention the release issues, with which the community is all too familiar). When we see a real problem (like yours) it's very important for us to get a fix on it A.S.A.P. =D