System has frequent hiccups of unresponsiveness

After anywhere from about a minute to five minutes after logging into the system, I start to experience what can only be described as a hiccup; The particular application that I am using at the moment, (I use gnome-terminal most of the time so it is most prevalent there, but I've also experienced it in firefox, pigdin, open office, and other applications ) becomes unresponsive to keyboard and mouse input until some sort of external action occurs. ( both closing / reopening the laptop lid and receiving and ssh connection have both caused the machine to become responsive again)

I've checked both the kernel logs and the X server logs, but nothing seems to amiss according to the system, save for an occasional APIC error in the kernel. ( which are nowhere near frequent enough to occur at the same time the intermittent hiccups occur)

I have Toshiba Satellite S7437 running hardy with the latest updates as of 1/28/08 applied.