Yes, you will notice the missing 333 mhz

MacMegasite - 10.2.8 Reducing Processor Speed?

I had this happen to me. I thought it was odd that I was maxing the processor so frequently, and that the 500-megahertz TiBook seemed almost as fast as the miniBook.

The page above suggests that a PRAM reset (Command-Option-P-R on startup) will straighten everything out, but that wasn't enough on my PowerBook. I had to also reset the Power Management Unit: With the machine off, press and release Shift-Control-Option-Power On at the same time. Nothing will happen, but wait at least 5 seconds. Power up, and check that you're back to normal.

You can verify that you're fixed with Xbench, or with the shell command 'sysctl hw.cpufrequency'.

Update: I rebooted today after installing QuickTime 6.4 and iTunes 4.1, and afterward, my CPU frequency was back at 533 mhz. Resetting the PMU (and only the PMU) straightened it out.