I had been looking at my G5 2.5 dual as potentially retiring it from seti use as the RAC I was getting was dropping and dropping and dropping and I just presumed it was too old to make any meaningful contribution. My cutoff point mentally is 500 RAC and I was getting awfully close to that until I noticed something:
For some reason, BOINC had nuked Alex's optimized clients and replaced them with the standard clients and my RAC was sometimes below 600. Ugly.
I deinstalled BOINC, downloaded the latest Mac Client, reinstalled the optimized client (using Dotsch's latest variant of Alex's client) and THEN my RAC rose to around 800.
Phew. That was close.
Any idea why or how this could have happened? Just an FYI for anyone who's seen dropping RAC without any obvious reason why.