I know Crucial doesn't. They time their modules conservatively. They make so much stuff for OEMs that they shoot for stability rather than performance. I've never had one that wouldn't run CL2 rock solid. I had some PC2100 modules that were pretty sweet overclockers. The PC2700 is less overclockable, but CL2 is no problem. I haven't tried the PC3200 that's rated at CL3, yet though.