Hi Glenn, I compared the molecule rendering speed with Mac X11 and Mac Aqua Chimera snapshots (version 1.2524) and found them to be the same on an Intel Mac PowerBook with Radeon X1600 graphics and on a Power Mac G5 with Radeon ATI 9800 pro graphics. Here are scores for the G5 system Aqua Molecule 1f4h (33805 atoms): Null Wire Stick BStick Ribbon Sphere Ops 59.8 59.8 3.4 3.7 11.1 6.0 13.4 X11 Molecule 1f4h (33805 atoms): Null Wire Stick BStick Ribbon Sphere Ops 70.8 86.3 3.4 3.7 9.4 5.9 14.9 (The aqua values are clamped to my display refresh of 60 Hz.) You could try this on your system using Tools / Utilities / Benchmark. You can click the "Show individual test controls" checkbutton and press the "Molecule" button to just run the molecule tests. If the numbers do come out much different for X11 versus Aqua could you use Help / Report A Bug... to send us the numbers? Using that dialog will send us the technical specs for your graphics. Tom