Spy - 3.0

Spy is a useless little tool that sucks up really important CPU time to display some info about your system load. Spy is as unobtrusive as possible. Its original goal was to take less screen space than the Mac OS X utility CPU Monitor. It does so by lodging itself in the menu bar.

Spy displays two kind of information, your CPU load and your network load.

The CPU load is represented with two small circles in the menu bar. The inner circle shows the system load, the outer circle the user load. Looking at the black line length gives instantaneous load reading. Average reading, if enabled, is provided by looking at the level of transparency on the rest of the circle. Spy supports multiple CPUs, either by showing one widget per CPU or by aggregating all the CPUs on one widget. To be honest if you have more than two processors in your Mac the display in this later mode is going to be too small for comfortable reading. The good news is you don't care, because there is currently no Macintosh with more than two processors available.

The CPU load can also be passed to a Griffin PowerMate if you have one, so the leds at the base of this cool device pulsate in rythm with your CPU . Try a good 3D game, you will finally be able to see how much your CPU is working while you frag those aliens. I haven't invented the idea, but when I saw the feature in unsanity.com's Cee Pee You I had to implement it as well.
The network load is always an agregate of all your network interfaces (ethernet, Airport, PPP over a modem). It shows two arrows, one up for the outgoing packets, one down for the incoming ones. The thickness of the arrow is relative to the max load of the network over the last 5 minutes. This means that if there is no network activity for a while, one byte send is going to be rendered as a big fat arrow.

Spy is free, but you get what you paid for: a piece of software without guaranties of any kind. It may work, but if it goes and erase your hard drive instead of its real job, well, too bad. This said my hard drive is still working.