Protools CPU meter Peaks

[EF]

I am trying to overdub some vocals on a song with the buffer set to 128 and the CPU meter keeps spiking and causing Protools to give an error message about increasing buffer setting. I disable any tracks that have reverbs or amplitude on them and this puts the solid green part of the CPU meter to maybe 15% but the thin line keeps jumping up to maximum every few seconds. I have set my system up the way digi suggests. And I have had no problems doing this in the past. I am relatively new to Mac's and wonder if there is any system maintenance that I need to do that would help the CPU performance. Do you need to defrag the drives? I have read that you don't need to in OSX but I really have no idea. If you do need to defrag, is there a utility built into the OS or do I need 3rd party software. I also have Digital Performer 4.5 on this system and the CPU meter in that program seems a lot steadier. My system specs should be in my signature. I am running PT 6.4. Any help or suggestions would be appreciated. I mey need to call digi tech support but I've heard horror stories about hold time.

Thanks,
Eric.

[MoreMeintheMonitors]

Make sure Energy Savers are off and, on the Options tab in the Energy Saver control panel, make sure that processor performance is set to 'highest'.

Are you recording to the main internal drive or a secondary drive?

[EF]

I have those settings set allready. I am recording to a second 250G SATA internal drive. I notice that the thin green line jumps around more during playback than if the session is stopped. This is probably normal though. It disturbing that a week ago the meter would jump some but I could record at 128 without any problems, but now I keep getting 6093(I think) errors. Any other suggestions would be appreciated. I wonder if a clean OS instal would help but the thought of reauthorizing everything keeps me from wanting to do that unless all else fails.

[tele_player]

I'd use Activity Monitor to see what else might be happening in the system.

[Ducky]

Just in case, remember that bypassed and disabled is different. In bypass mode, plugins still use CPU. Disabled the system ignores them. I am not sure what happens to plugins on a disabled track. to be sure, disable the plugins on the disabled tracks, then disable the track. PTLE 6.x has been very flaky about truly disabling and even unloading plugin stuff. Any D-Verbs in your session? Remember to dither them down to 16 bit right before the verb.