I remember back when we first got XL 7, I was completely ape-shit for caustics. It was right after XL 7 was released, I had set this scene up to render over a long weekend (I had done some tests and determined that caustics took an assload of time to complete)... anyway, at the time I was working off of a Blue & White Yosemite G3 400 MHz and (only) 192 MB of RAM (it seemed like so much back then!), so I let this scene rip, and THREE DAYS LATER it had barely started. Needless to say, I cancelled that crap without a second thought, and haven't really given caustics much more than a fleeting glance since. Fast forward to this past weekend... I just bought a dual-2.0 GHz Xeon (as in "two chips, each running at two gigahertz") workstation with an nVidia Quadro4 900XGL video card... cost a pretty penny, but it seems to be worth it. For kicks, I opened up this old nautalus scene file, and the damned thing rendered, completely, in under thirty-one minutes. Sick, eh?