MIDI Arpeggiator

Arpeggiator is a missing piece in my music setup.
An Arduino and several MIDI connectors are available in the mess...

But is it possible to make a simple arpeggiator ? Do the Arduino have a sufficient CPU for this task ?
Just wanted to known before starting to write the code.

Thanks !

PS : it really nice to work with the Arduino. I've interfaced a Touchpad and MIDI. 2D control (ie: cutoff and resonnance).