Here’s a quick tip: if you have a monitor connected digitally to your Mac, but you have it powered off, your Mac may hiccup or stutter every second or two. The mouse and keyboard will be momentarily unresponsive, the clock will briefly pause, and if you’re playing video, the system will consistently drop a frame or two. It’s enough to drive a motion designer mad.

In my case, I had two monitors attached to my Mac Pro via DVI, but one of them was powered down. The stuttering made it difficult to work, and impossible to QC video.

The fix? Power up that second monitor, or physically disconnect it from the system.

My best guess is that the operating system is polling the display , possibly for HDCP compliance.

If you can reproduce this on your system, please consider filing a bug report with Apple. You can use Apple’s Mac OS X Feedback page, or the Apple Bug Reporter if you are a registered developer.

Open the Date & Time system preference pane on Mac OS X

Activate Mac OS X setting for speaking the time aloud on the half-hour

When you’re working on a project, it’s all too easy to get lost in the zone. You’re getting work done, but you’re unaware of the passage of time. While this state of flow has some huge benefits, it makes it hard to manage your time effectively, especially if you’ve got multiple deliverables and tight deadlines.

Mac OS X has a built-in system option that speaks the time aloud on the interval of your choice—every hour, half hour, or quarter hour. It’s pretty unobtrusive, and the new voice for Leopard is vastly improved over the speech synthesis from Mac OS 9.

I have this enabled on my workstation to help keep me on track through the day. It just takes a few clicks. Open System Preferences, and open the Date & Time preference pane. From there, choose the Clock tab, and tick the Announce the time box.